3 - Centre National de Recherches Météorologiques - Météo France


3 - Centre National de Recherches Météorologiques - Météo France

Researchanddevelopment:annual report2007

Table of contentsWeather forecasting models page 4Synoptic NWPMeso scale NWPCyclonic ForecastingThe AMMA campaign page 16Use of data collected during the AMMA campaignFirst results from studies led within the AMMA campaignStudies of meteorological process page 20Cyclogenesis and previsibility studiesMeso scale eventsClimate and climate changes studies page 28Atmosphere and environment studies page 32Hydro-meteorologyOceanography (modelling & instrumentation)Atmospheric environmentAtmospheric chemistry and air qualityAvalanches & snow cover studiesInstrumentation for research page 48Aircraft instrumentationOn site instrumentation and teledetectionCommunication & Promotion page 54Appendix page 56

Several papers in the following annual reportdescribe important aspects of the currentresearch whose aim is to improve theNumerical Weather Prediction systemARPEGE. Four actions deserve particularattention :- the improvement of the atmospheric model,including a significant increase in the horizontaland vertical resolutions were madepossible by the new computer Nec SX 8Rwhich is operational since the beginning of2007. In addition to a spectacular improvementin the ARPEGE performances, this developmentcan be considered as a first steptowards the next increase in resolution whichwill make possible, as from 2009, a directcoupling between ARPEGE and the AROMEhigh resolution model.- the assimilation of new observations hasbeen the subject of an intense activity, in particularfor the observations produced by theMetOp satellite. Very promising results havebeen obtained with the assimilation of theIASI sounder. A specific effort is devoted tothe assimilation of observations related tothe water cycle. Recent progress have madethe assimilation of the GPS radio possibleoccultationdata in an operational context,with a very positive impact over the Southernhemisphere.- the ensemble forecast is a relatively newresearch domain at CNRM. The developmentof new methods for the perturbation of theinitial conditions has been achieved in 2007.Presently, Météo-France operates a state ofthe art ensemble forecast which feeds up theTIGGE Grand Ensemble. TIGGE has been setup by the THORPEX program of WMO in orderto initiate academic and applied researchwhich focuses on the use of multi-modelensembles for probabilistic predictions.- the development of an ensemble assimilationsystem proved itself to be a particularlypromising method to evaluate background2 . Research and development: annual report 2007

errors depending on the current meteorologicalsituation. Recent results show very goodperformances on relevant error statistics withonly 6 members. This performance makes itpossible to envisage the operational implementationof this technique in a very nearfuture.Improving the ARPEGE model does not onlymeet operational aims. Most developments,either on physics or on dynamics, are done inclose cooperation with teams developing thelimited area models ALADIN, Méso-NH andAROME as well as with teams developing climatemodels. At the same time, developmentsare also under way to include the same externalizedscheme for continental and oceanicsurfaces in all these different models.Additionally, it must be emphasized that theARPEGE model is also a powerful researchtool which is a core component to investigatecyclogenis and fronts dynamics, as it isshown in this report.Éric BrunHead of Research at Météo-France Eric Brun, head of CNRM, duringhis opening lecture at the atmospheremodelling workshop, in January 2007.3 . Research and development: annual report 2007

Numerical Weather Prediction2007 saw the first quasi real time experimentation of the AROMEprototype which should be operational by the end of 2008. Theresearch teams not only worked hard on AROME but they alsoimplemented a new spatial resolution for ARPEGE and for ALADIN.Moreover, data assimilation systems have been improved, andspecific forecast tools for aeronautic needs have been developed.In the meantime, cyclone forecasting made some significant progress.Synoptic NWPAssimilation of MetOp dataThe Metop satellite, launched in October2006 by EUMETSAT, is the first Europeancontribution to the constellation of operationalpolar-orbiting satellites. The instrumentsonboard MetOp, innovating for some, in thecontinuity of existing instruments for others,provide data which have started to be assimilatedin the numerical weather predictionmodels at Météo-France.The ATOVS instruments (AMSU-A, MHS, HIRS)measure radiances which can be directly linkedto atmospheric temperature and humidity.These data are now a useful addition tothose originating from American satellites inthe operational models (see Figure). TheASCAT scatterometer observes winds at theocean surface in the continuity of the ERSscatterometer, but with a swath twice asbroad. The most prominent instrument onMetOp is the Michelson Interferometer in theinfrared spectrum, IASI, developed by CNES incollaboration with EUMETSAT. The amount ofdata collected by IASI is more than a hundredtimes greater than that provided by soundersfrom the previous generation such as HIRS, thusresulting in a finer description of the atmosphericvertical structure. The assimilation of ASCATand IASI data is planned for 2008. Finally, theGRAS instrument will soon provide GPS radiooccultationmeasurements similar to thoseMétéo-France recently started to assimilate.Beyond the application to numerical weatherprediction at short to medium range, thedata collected by IASI will contribute to a betterknowledge of the atmospheric compositionin minor constituents of which radiativeproperties are of utmost importance for theclimate. 1Assimilation of GPS radio occultation datafor Numerical Weather PredictionSatellite observations of the Earth’s atmospherecollected, thanks to the GlobalPositioning System (GPS), are now used beneficiallyat Meteo-France to improve numericalweather forecasts. The radio-navigation signalssent by the American GPS satellites located at a20200 km altitude are refracted by the Earth’satmosphere. The atmospheric refraction measuredby GPS receivers in lower orbit (between400-1600 km altitude) enables then to characterizethe temperature and water vapour distributionsin the atmosphere.In 2006, the USA/Taiwan FORMOSAT-3/COS-MIC mission launched six such GPS radiooccultation receivers. Numerical weather forecastexperiments conducted at Meteo-Francehave shown that the bending angle data collectedby these satellites, as well as similardata collected by the German satellitesCHAMP and GRACE, helped improve numericalweather forecasts by reducing the errors inthe estimated initial state of the atmosphere.The largest improvements were observed inthe traditionally under-observed regions(Southern hemisphere) and those regionswhere the addition of high vertical resolutiondata is critical to help improve the atmosphericdescription in the model (tropopauseregion).As a result of this study, Meteo-France’s globalnumerical weather prediction model ARPEGE,as well as the limited-area model ALADIN overEurope and over La Reunion Island, have beenoperationally assimilating GPS radio occultationbending angle data since September2007. 2ARPEGE : seamlessglobal to mesoscaleforecasting systemThe global data assimilation and forecastingsystem of Météo-France, Arpege, as well asthe hydrostatic Aladin models which are coupledto it, change and improve continuously.The following paragraphs thus summarize theobservation system extension and the newdevelopments in data assimilation or in theparameterization schemes.The overall framework within which all thesechanges are integrated also undergoes someevolutions. Foremost, a change of verticalresolution will be applied to all the Arpegeand Aladin models: the atmosphere will berepresented with 60 vertical layers instead ofthe 46 currently in operation. It has been chosen,in this instance, to focus the vertical refiningaround the altitudes 10-12 km in orderto better represent the jet-streams. To betterrepresent jet-streams, the vertical refining willbe focussed around the 10-12 km altitudes.They influence many aspects of the weatherevolution. Precision in the vertical computationsis improved by activating a numericalscheme developed at ECMWF in Reading.Furthermore, the Arpege horizontal resolutionis also increased. Everywhere around theglobe, it tends to be less than 100 km, andeven smaller than 50 km around La RéunionIsland. In the Europe-North Atlantic broadarea, Arpege has a finer resolution thanECMWF model, with an average resolutionsmaller than 20 km from Iceland to theCaspian Sea. Resolution reaches 15 km overFrance. The horizontal resolution changescontinuously, therefore avoiding breaks thatresult from lateral coupling. This new resolutiongives details of the internal structure ofstorms, as illustrated by the figure, with veryrealistic cloud systems.These changes have been extensively testedduring the last three months of 2007 andbecame operational early in 2008. 34 . Research and development: annual report 2007

1 Data coverage from AMSU-A sounders used in operations in the ARPEGEmodel assimilation, over a 6 hour assimilation period (MetOp is in blue).23 Geometry of the GPSradio occultation technique:the atmosphere refracts theradio signal sent bya GPS transmitter;the refraction angleobserved by a GPS receiverenables to characterizethe atmospheric refractiveindex at the tangentpoint (T).4 The 08/11/2007 strong North Sea storm which amplified all day long.The related cold front, well marked, undergoing further internal fine scaleperturbations that caused severe damages in the North of France (compositeradar reflectivity composite, top left panel). The Arpege operational version(bottom left panel) does not represent such fine structures, but it did forecaststhe storm. On the other hand, the new version of Arpege (right panels) furtherforecasts the front organization and it suggests the internal perturbation, both inits dynamical components (bottom) and in its cloud structure (top). Top rightpanel: 3 layer composite cloud cover, high level clouds (H), mid-level clouds (M)and low-level ones (B). Bottom: wind (barbs, kt) and relative vorticity (shading)at about altitude 1500 m. A maximum vorticity band is a good indicator of afrontal zone, while a spotty maximum outlines a vortex. Contour interval: warmcolours 5 10 -5 s -1 from light red, 2,5 10 -5 s -1 below, cold colours, negative values.PEARP 16/01/2007 18TUvalid. 18/01/2007 18TU (+48h)1. 3. 5. 10. 15. 20. 25. 30. 35. 40.mgp Example of a 48 h uncertainty forecast by the upgraded global PEARP fromthe 16/01/2007 18 UTC, for the 18/01/2007 18 UTC. On that day, a strongstorm hit the North Sea and nearby south-eastern countries. Contours are500 mbar geopotential height (a pressure-like field, altitude about 5.6 km,contour interval 10 damgp) forecast by the ensemble mean. Shading showsthe uncertainty as the standard deviation of the differences between ensemblemembers (interval: 5 mgp). Far from being uniform, uncertainty grows for specificareas shown in red and where it turns out that active bad weather systemsare often located.A first upgradeof the Arpege ensembleprediction system(PEARP)PEARP, for Arpege ensemble forecasting inFrench, is Météo-France ensemble predictionsystem, initially developed by theForecast Department. It is an ensemble targetedtowards short range probabilistic predictions,that is for the following next 3days.On top of an unperturbed control forecast,PEARP consists in 10 more forecasts whoseinitial conditions are subtly non-randomlymodified. The differences between the evolutionsin time of the 11 forecasts provide ameasure of the uncertainty and enable tooutline the probability distributions of thepredicted parameters. In the operationalversion, the perturbations that are used toprepare the various initial states are onlycomputed within a domain restricted toNorth-Atlantic and Europe. CNRM initialaction on PEARP has been to change theseperturbations. Firstly, they are, from now on,computed over the whole globe. Secondly,part of the forecast uncertainty comes fromthe past, through the evolution of perturbationsfrom previous runs during the periodpreceding the initial forecast time.Finally, a small part of the uncertainty aboutthe knowledge of the initial state is derived5 . Research and development: annual report 2007from the latest variationnal analysis and isused to adjust the amplitude of the final perturbationsthat are then added to that analysis.This is the first step of an evolution thataims to develop a state-of-the-art probabilisticforecast system, a step mostly directedtowards improving Météo-France contributionto the WMO supported TIGGE project ofcollecting global ensemble forecast. Thisnew version of PEARP became operational infebruary 2008. 4

Estimation of forecasterrors with a smallensemble of forecastsand an optimized spatialfilteringAssimilation systems such as the Arpège,Aladin and Arome models enable to correctforecasts with observations. This is done byaccounting for forecast error statistics. To estimateforecast errors, an appealing approachis to simulate the time evolution of errors byusing an ensemble of perturbed assimilations.The idea is to add perturbations whichsimulate uncertainties at play, and to makethem evolve through the analysis and forecaststeps.The ensemble size is a crucial factor toobtain an estimate which is both robust andnot too costly. However, using optimizedspatial filtering techniques allows the requiredensemble size to be reduced in order toreach a given accuracy (or vice versa toincrease the accuracy for a given ensemblesize). The idea is to calculate a local spatialaverage of statistics, which allows the statisticalsample size to be strongly increased.These notions are illustrated in the figurewith four estimates of the error variance mapof vorticity near 500 hPa. Panel (a) correspondsto a reference, which indicates thatthe errors are larger over the Atlantic andPacific Oceans, and also in the SouthernHemisphere. Panel (b) is an estimate froman ensemble of 6 random realizations afteran optimized spatial filtering. The resultingestimate is more accurate than the raw estimationsfrom 6 or even 220 realisations(panels (c) and (d) respectively).An operational implementation of thesetechniques is considered for 2008, in orderto describe the dependence of errors on theongoing weather situation. 5Study of alternativeformulation forIFS/ARPEGE/ALADIN/AROMEdynamic kernelThe non-hydrostatic (NH) dynamical kernel ofour Numerical Weather Prediction tool is oneof the key elements of the new AROME system,currently under tests for a future operationaluse (the other elements being thephysics and the data assimilation). In parallelto this use at fine scales in small limited areadomains, other types of applications areconsidered for the future. Work is underwaywith the ECMWF to see if the kernel is relevantto the global IFS model in NH mode. A cooperationwith the HIRLAM group is also in progressfor large limited-area domains.Such configurations depart significantly fromthe AROME one in many respects (geometry,inclusion of physics and algorithmic choices,...).Robust and accurate algorithms arerequired for a possible use of the NH dynamicalkernel for this wide range of applications.For this, research mainly involved theincrease of the robustness for large timestepsthrough a revision of the discretisationof some non-linear terms, and the improvementof the intrinsic accuracy through theimplementation of a preliminary version withthe discretisation of vertical finite elements. Alonger-term work about the possible replacementof the prognostic NH variable set isundertaken with the aim of a more naturalinclusion of finite elements. 610 m winddata assimilationinside ALADIN10 m wind observations assimilation is arather tricky/difficult task. As a matter of fact,wind near the ground depends a lot on smallscale orography that can be quite differentfrom large scale model orography. Besides,data are also influenced by small scaleground parameters such as vegetation type,height. At last, a wind measurement in mountainousareas can represent a phenomenumthat has a time limitation is limited in timeand is of little importance for large scales.However, for limited area models whose surfacecharacteristics are closer to reality,these observations can bring useful informationto a data assimilation system. Becauseof the high temporal and spatial cover(cf figure a); we tried to test their impactinside the limited area model ALADIN. Forthat, first we selected stations, which presented,over the test period (4 month), astrong correlation with values forecasted bythe ALADIN model.The main impact of these observations islocated inside the atmospheric boundarylayer as shown in figure b, the vertical crosssection shows that the impact is importantbelow model level 35, that is to say at 1.5 km.The only relevant improvement of 10 m windobservations is the reduction of the groundpressure bias inside ALADIN, which is a knownflaw of that model. That effect is possiblethanks to the correlation of the model errorsbetween surface pressure and wind. 76 . Research and development: annual report 2007

ab5c Forecast error variances of vorticity (in 10 -9 s -2 ) near 500 hPa.Panel (a): reference.Panel (b): filtered estimate from 6 random realizations.Panels (c) and (d): raw estimates from 6 or 220 realizations, respectively.The filtered estimated is the closest one to the reference.ad6Valeurs Propres20-2-4-6-870 20 40 60 80 100 120 An example of the NH dynamical kerneleigenfrequencies, analytically diagnosed for thecase of a particular vertical finite-elementdiscretisation with 60 irregularly-spaced levels.Green: logarithm of the real part;red: imaginary part (x10000). The appearance of aweak imaginary part indicates that the systemwould be unstable with this particulardiscretisation.With this kind of analysis for the responseof the system it is possible to anticipateits behaviour without heavy developments.b a : 10 m wind observations available for each analysis.b : Vertical Cross section over France showing differencebetween two analysis at 12 h 00, one with 10 m windobservations, the other one without7 . Research and development: annual report 2007

Meso scale NWPSince september 2007, the AROME modeluses initial conditions provided by its owndata assimilation system instead of thoseproduced by the ALADIN-FRANCE operationalsuite.This system is based on the ALADIN-FRANCE3D-Var scheme that is operationally runningat Météo-France at regional scale since June2005. It uses high temporal and spatial frequencyobservations (RADAR measurementsfor example) to the best possible advantage,and a rapid forward intermittent assimilationcycle in order to compensate the lack of temporaldimension in the 3D-Var scheme.Observations every 3 hours (instead of 6 inALADIN), are assimilated using the previousmodel forecast as a background to produce anew estimate for wind, temperature, humidityDoppler radars observations allow to describethe tri-dimensional structure of precipitationsand of air flow within a precipitatingsystem with a high temporal and spatialresolutions. Consequently, these data willplay a crucial role in the retrieval of AROME’sanalyses, which will be the starting point toforecast severe weather. For this purpose,studies are currently under progress in orderto take into account radars from the Frenchnational network ARAMIS in the AROME assimilationsystem. As a first step, observationoperators have been developed to simulateradial velocities and reflectivities using themodel’s variables.The assimilation of Doppler winds in theAROME 3Dvar has been validated for severalconvective cases and is still being evaluatedon a daily basis in a pre-operational configu-The AROME modeluses its own assimilationUse of radar datain AROMEand surface pressure fields. The others fieldsare cycled from the background.Observations that are assimilated in the systemare currently those of the ALADIN-FRANCEoperational suite. Works will be soon completedon the use of other types of observationssuch as wind measurements by Dopplerradars.This data assimilation system has been firstlytested on different precipitating cases. A dailyassimilation cycle has been performed sinceSeptember 2007. Forecast evaluation, using,for example, standard scores against observations,shows a general benefit of the use ofthe AROME analysis during the first 12 hourforecast ranges. After 12 hours, the influenceof lateral conditions becomes more importantthan the initial conditions one. 8ration. It has been found that, when somefavourable sampling conditions are present,short term forecasts of precipitations areimproved thanks to a more realistic analysisof convergence structures in the boundarylayer (figure).The assimilation of reflectivities is more complexbecause microphysical variables are notconsidered as control variables in AROME,and because of the difficulty to linearizewater cycle processes. A 1D statistical inversionmethod, which allows to retrieve relativehumidity profiles from reflectivities, isfirstly applied by using the model state in thevicinity of the observation as a probablesource of information. These profiles arethen directly assimilated in the 3Dvar.Encouraging results have been obtained sofar and work is still in progress. 9Validationof the Aromemesoscale model in testThe mesoscale Arome model is currently onits final phase. During the year 2007, thenumerical suite saw several important evolutionsfor the production of fine scale forecasts.First, thanks to the computingresources of the supercomputer NEC, fromearly January 2007, it was possible to enlargethe size of the domain in order to cover thewhole of Metropolitan France.Then, during the year 2007, practical experimentationsmanaged in the framework of thePARME (support to the implementation) projectwith forecasters coming from regional aswell as central services allowed to detectsome youthful defaults of the model. Some ofthem are already or on the way to besolved. For example, some dynamical tuningsnot well fitted to the horizontal scale of Aromehave been revisited and some improvementsof the physics have been evaluated such as anew scheme for the shallow convection. Theobjective validations such as comparisons offorecasts with respect to observations alsoallowed to detect several systematic bias.Some of them found a solution such as theimplementation of a specific scheme for thecanopy that has proved to improve the scoresof the 2 metres temperature and of the 10metres wind. Others, such as the overestimationof the heavy rainfall need to be re-examined.Finally, the implementation of theassimilation at the end of September 2007ends a year full of changes for the Aromemodel.To conclude at the close of 2007, one couldsay that the quality of the forecasts dependson the type of parameters and on the weathertype. Objective comparisons with respect toobservations are of the same level of accuracyas the ones in the Aladin model. The experimentationsdone by forecasters also showedsome successes, in particular, the triggeringof diurnal convection or as drawn in the figurebelow, in the cloudiness forecast. The nextchanges that will occur before switching tooperations will contain, in particular, the assimilationof the Doppler wind data. 108 . Research and development: annual report 2007

2555220210522202222221555251522222222525102525255252522252222222255220.50.10.1220.10.520.10.50.5252222525-1 - 0.5 0.5 - 2 2 - 5 5 - 10 10 - 15 15 - 20 20 - 30 30 - 40 40 - 55 55 - 75 75 - 100 100 - 1500°0°ICMSHAROM+0012 - - 0 - field : PRECIPA50°N0.50.50.150°N150.10.510100.1Cumulated rainfallsbetween 00 and 12 UTCDecember the 8 th , 2007:raingauge measurements (a),simulated by an AROME forecaststarting at 00 UTC and usinginitial conditions provided by theALADIN analysis (b), and theAROME analysis (c). 0.5 2 5 10 15 20 30 40 55 75 100 150 2500° ICMSHAROM+0012 - - 0 - field : PRECIPA100.5a81520101015100. Rain-band associated to a coldfront that has occurred in NorthernFrance November the 8 th , 2007, at18 UTC:(a) composite reflectivity pattern,divergence analyses at 950 hPadeduced from the AROMEassimilation system (b) withand (c) without radial velocities(blue-green contours denoteconvergence; in (b): red squaresshow radars that have been takeninto account, blue dots radialvelocity profiles that have beenconsidered in the analyses).°Na0.50.50.5cSatellite imagein the visible channelfor the 07 thof August 2007at 12 UTC.b10cSuperimposedthe 12 hours forecast ofthe Arome model in testbased on the 07 thof August 2007at 00 UTC for the totalcloudiness parameter.9 . Research and development: annual report 2007

Tests of a turbulentcanopy schemein AROMEA new Surface Boundary Layer (SBL)scheme developed by GMME has been evaluatedin AROME. This scheme, namedCANOPY, is integrated within the surfacescheme. It consists in adding 6 verticallevels between the soil and the lowestmodel level (which is currently at 17.5 m inAROME). 2 metres and 10 metres diagnosticsare computed using a turbulencescheme on these 6 added levels. Contrary toprevious surface boundary layer diagnostics,CANOPY scheme affects all the resultsof the numerical simulation. Indeed, fluxessend by the surface to the atmosphere arechanged.The scheme has been evaluated during2 months: January and July 2007, over South-Eastern France. The comparison with the 351observation stations over the domain isimproved as showed in figures (a) and (b) :2 meters temperature bias and root meansquare errors are reduced. AROME SBL scoreshave now a quality at least equivalent or betterthan the ALADIN ones. 11Impact of the useof a new shallowconvection schemein AROMEThe horizontal resolution of AROME (2.5 km)is not sufficient to explicitly resolve all typesof clouds, and a subgrid representation ofcumulus clouds and fractional stratocumulusis still needed. A new shallow convectionscheme has been developed in AROME, called“EDKF” (Eddy-Diffusivity-Kain-Fritsch) toimprove the mixing in the dry or wet convectiveboundary layers, associated to the subgridthermals. This scheme is based on themass-flux scheme of Soares et al (2004)improved by a formulation of the cloudyentrainment/detrainment of the originalMeso-NH scheme (Bechtold et al., 2000). Anon-local mixing is also applied to the wind,in addition to the mixing yet realized by theturbulent scheme via the eddy-diffusivityapproach.This new parameterization is currently testedwith AROME daily runs and shows significantimprovements on boundary layerclouds. A positive impact is also the removalof “herringbone” patterns on the low levelwind which is frequently produced inconvective boundary layers with weak winds(figure 12). This noisy dynamical structurewas relative to an insufficient mixing in thesimulated boundary layer, inducing typical“rolls”, especially at kilometric resolutions,when eddies are partly resolved and partlyparameterized. The new EDKF convectionscheme contributes to the mixing relative tothe thermals, modifying both the thermodynamicaland dynamical profiles. 12Local forecastingof low visibilityconditions on airportAccurate forecasts of the onset and burn-off offog or low clouds matter a great deal for airportssince the frequency of landings and taking-of issignificantly reduced with low visibility conditions.COBEL-ISBA is a single column numericalmodel (developed jointly with Laboratoire d’aérologieand Université Paul Sabatier) whichaims at forecasting fog and low clouds situations.It is in operational use at the Paris-Charles de Gaulle airport since 2002.In 2007, research activities have mainly focusedon the initial conditions of temperature andhumidity of this model. These are given by anassimilation scheme which combines localobservations and a guess, i.e. a forecast fromthe previous forecasting cycle. It has beenshown that the vertical influence of observationson the initial profiles follows a strong diurnalcycle.As a consequence, a new assimilation scheme,which takes more into account this variability,has been developed : an Ensemble KalmanFilter (EnKF). The correlation between humidityand temperature uncertainties in the guess hasalso been accounted for. This work also showedthe impact of the initialization of fog andlow clouds, and steps have been taken toimprove it.In 2008, work on the assimilation scheme willbe pursued, using the numerous data from thefield campaign “Paris-FOG”, in which COBEL-IBSA took part by providing daily forecasts. Themodel is being installed on two other airports :Paris-Orly and Lyon-Saint Exupéry. Our goal is tomake COBEL-ISBA available for operational useat the Lyon-Saint Exupéry airport by the winterof 2008-2009. 13Targeted uplink of georeferenced weather informationfor commercial aircraftsSelected and launched as part of the 6 thFramework Programme of the EuropeanCommission, FLYSAFE aims at defining andtesting new tools and systems which willcontribute towards the safety of flights ofall aircraft. This high-level objective is toprovide crews with decision aids on thethree “threats” which play a major role inaccidents, amongst which adverse atmosphericconditions. Météo-France, the MetOffice, the DWD (Deutsche Wetter Dienst),the DLR (Deutsche Zentrum für Luft andRaumfahrt) and University of Hannoverhave developed ground-based nowcastingsystems (WIMSs: Weather InformationSystems) focussed on weather phenomenonsthat have an impact on aviation:Cumulonimbus, In-flight icing, Clear AirTurbulence, Wake vortices. The WIMS productsare georeferenced weather objectsthat describe hazardous areas with a polygonassociated to several meta-informationssuch as the severity of the confidenceindex associated to the forecast. A GroundWeather Processor concentrates the WIMSproducts and answers aircrafts requests.The GML-based exchange model that hasbeen put in place and the associated webfeaturesare compliant with the specificationsof the Open Geospatial Consortium,which will contribute to the interoperabilityand ease the operational implementation.This system will be evaluated in 2008 withtwo flight-test campaigns in which theSAFIRE ATR42 will be involved. 1410 . Research and development: annual report 2007

3K4,03,02,01,011SUDE005a100959012Module : min=0.0785159468651 max=7.88577312231 moy=3.5888221783635430°5454,0 m/s50°N0,08530 3 6 9 12 15 18 21 24 27 30ÉchelleSUDE005334,03,02,09031,00,00 3 6 9 12 15 18 21 24 27 30Échelle T2m scores for January (a)and for July (b) 2007:AROME-Reference (pink),AROME-Canopy (blue), root meansquare errors on the top, biasat the bottom.b8554343340.1 - 1 1 - 2 2 - 3 3 - 4 4 - 5 5 - 7 7 - 10 10 - 1543423334a13Module : min=0.024394646287 max=7.46915210783 moy=3.182012593330°4,0 m/s354454450°N432343 3332324233b Fog can dramatically reduce airport traffic :persistent fog on the London-Heathrow airport,December 2006. Photo by Tim Ockenden, Associated Press.223433323312233332344434243354423422 Situation of the 30 th of July 2007 at 14 h TUin the North-West of France forecasted withAROME. Module and vector of wind near theground in the standard version of AROME(without EDKF) (a) and with EDKF (b). FLYSAFE overall concept1411 . Research and development: annual report 2007

New generation observationsand meso-scale modelfor aeronautical icing risk detectionDevelopmentfor a rain occurrencewarning productThe present work is conducted within thescope of FLYSAFE, a 4 year Integrated Projectof the 6 th framework of the EuropeanCommission started in February 2005. Inorder to increase aircraft safety, one of themain objectives of the FLYSAFE project is toimprove weather information supplied toflight crew members. In the frame of FLYSAFE,Météo France is currently improving its nowcastingtool for the detection of in-flight icingareas called SIGMA.Innovative SIGMA developments include theuse of new generation observations such asvolumetric radar images and high resolutionMeteosat Second Generation satellite imagery,as well as the new Météo-Francemesoscale non hydrostatic NumerocalPrediction Model AROME. SIGMA algorithmhas been redesigned to be able to takeA thunderstorm nowcastingsystem for improvingcommercial flights safetyThe aim of the European project Flysafe isto improve the New generation IntegratedSurveillance System for commercial flightsby 2015. The three risks addressed aremeteorological factors, collision with theterrain and collision between aircrafts.Among the meteorological phenomenaaddressed, thunderstorms are handledthrough the development of a prototype“Weather Information Management Systemfor Cbs”, which is led in cooperation withthe German DLR, the French ONERA, theBritish Met Office and the University ofHanoverMétéo-France with DLR addresses two spatialscales: the so-called Terminal ManoeuvringArea (TMA) and the regional (i.e.European) scale. The goal is to identify, todescribe and to forecast thunderstorms at aone hour range using an object representation,with a high refreshed rate. For the TMAadvantage of these new observation inputdata elaborated by CMS ( Centre de météorologieSpatial) and CMR (Centre de météorologieRadar).Owing to these new observations, moreemphasis is put on observations comparedto NWP input data, and supercooled liquidwater diagnostic is now enhanced.In parallel to the improved observations, thenew NWP model AROME produces humidityand temperature fields with a much betterspatial resolution as well as new microphysicsfields which are very useful for diagnosticsand the forecast of super cooled liquidwater areas.Work on calibration and evaluation of the newSIGMA algorithm will carry on in 2008 with twoflight tests campaigns to be held in Februaryand August 2008 in the scope of FLYSAFE. 15scale, the data used is mainly the advancedAramis radar network data: 3D scans andtheir 2D synthesis, and dual polarizationdata for hail detection; Doppler winds areused for detecting large wind shear. Theforecast of maximum thunderstorm cell topis based on thermodynamic profile analysis.For the European scale, a radar mosaicis used, which includes data from neighbouringcountries, while handling their timeshift. Regarding the evaluation, diagnosedthunderstorm objects are checked againstcloud-to-ground lightning data, and againstthunderstorm objects diagnosed usingsatellite data. Forecast thunderstormsobjects are diagnosed using a newapproach which allows for uncertainty intime and in space.During 2008, a further evaluation will implyon-board radar data collected during aflight test experiment. 16In order to open a rain occurrence warningservice, we have settled and assessed a rainnowcasting suite. The service is specific toeach of the 38.000 French municipalities. Itcombines a warning message one hourbefore it rains, and gives more detailedinformation on the forecast rain time series.The forecast method is based on rain patternsmovements analysis using a radarmosaic, followed by an extrapolation of thenational rain depth radar estimate. Raindepth are translated in space without achange in magnitude. Using the rain depthestimate allows to benefit from its pixel-specificquality data, and the observation qualitycan hence be dynamically translated inservice quality.It was evaluated with 4 months of data,using the actual rain depth estimate as thereference. The criteria used were userorientated,and their median values werecomputed among all the municipalities;the false alarm rate amounts to 37 %,which is acceptable; the non-detectionrate is remarkably low (3 %) and the meananticipation before rain starts is 25minutes, which is below the objective. Thisnowcast is actually difficult because itaddresses quite low levels of rain. As thequality is not homogeneous over the country,this leads to open the service for only alimited part of the territory.Plans for 2008 include the use of animproved rain depth estimate, on deepeningand enlarging the evaluation, and onimprovement addressing the remainingshortcomings. 1712 . Research and development: annual report 2007

15 SIGMA icing diagnostic for the 7 th ofDecember 2007 at 13 UTC, at 800 hPa,showing an area of moderate to severeicing conditions in red, an area ofmoderate icing conditions in orangeand light icing risk in yellow.16 Mean values of anticipation over rain start for the rain warning product.Color scheme : black < 30’ < blue < 25’ < green < 20’ < yellow < 15’ < red. Flysafe and thunderstorms :enabling pilot to safely avoidthunderstorms. On June 2005, 23 rd ,at 13 h 45, near Paris, aircrafts(tracks shown in red) have a difficulttime moving around thunderstorms(shown as green, yellow and redpixels) before landing or evenentering it, especially for those inthe middle of the bottom halfbecause they did not get an earlyenough accurate picture of thethunderstorms locations.1713 . Research and development: annual report 2007

Cyclonic forecastingA specific cyclone initializationMétéo-France Regional Centre based in LaRéunion island watches over the south-westIndian ocean cyclones, an international dutyentrusted by WMO. Numerical modelling hasbecome an essential tool to forecast cyclones.The model initialization uses huge amountof data, mainly satellite measurements.However, data actually used in the cyclonebody are very sparse (figure a) because ofcloud, rain or strong wind contamination.Thus, the cyclone structure and intensityanalysis is/are very difficult. Dvorak analysis,that forecasters perform by using satelliteimagery, gives reliable estimates of themain cyclone characteristics. Forecastersuse satellite imagery for (a) Dvorak analysiswhich gives main characteristics of a lowatmospheric pressure system.Based on some of these estimated parameters,analytical models can compute the correspondingthree-dimensional cyclonestructure. Pseudo-observations, deducedfrom the latter, are assimilated in the Aladin-Réunion model since December 2007. Theyconsiderably improve cyclone analyses andforecast positions (figure b). Great benefitsare also visible on intensity forecasts.Forecasts about intensity also greatly benefitfrom them.In the years to come, the use of satellite measurementsin cloudy or rainy conditions willspread on. Another important progress forcyclone forecast is to improve the ocean description,since the ocean is the main energysource for the cyclone development. 18The effect of La Reunion Islandon the tropical cyclone Dina (2002)The intense tropical cyclone Dina directly affectedLa Réunion Island on 22 January 2002, causingimportant material damages. This event isan interesting case study to investigate theinteractions between the steep orography of LaReunion Island and a cyclone.For this purpose, two simulations wereconducted with Meso-NH model zooming onLa Reunion at a 4 km horizontal resolution:• the first named “Island” with La ReunionIsland,• the second named “Ocean” in which LaReunion Island has been replaced withocean.Both simulations give very similar tracks ofcyclone Dina; “Island” shows a very slightnorthward deflection, which has beenobserved in reality but in a more pronouncedway. The island seems to reduce naturaloscillations existing in the eyewall: thecyclone intensity for “Island” is then weaker.Big differences can be seen on the windfield with, for “Island”, weaker winds and amarked subsidence on the lee of the island.When the strongest winds reached theisland, the stream goes over the islandrather than around it. This excites an orographicwave, which is associated with theintrusion of stratospheric air, as shown bycomparing figures 1a and 1b. This simulatedwave, associated with maximum winds, isconsistent with the observation of strongwinds which have devastated forests in theCilaos cirque, yet sheltered.In addition to the understanding of thesemechanisms, high-resolution simulationsare very useful to estimate cyclonic windsand rainfalls over the whole island. Meso-NH has been able to simulate realistic characteristicsof a mature tropical cyclone; in afuture work, we will focus on an earliestcyclone life stage: the cyclogenesis. 19Upper ocean layerresponse to cyclonicconditionsIn spite of significant improvements of hurricanestracks prediction during the lastyears, their intensities are still affected byimportant uncertainties. The poor resolutionand the lack of coupled ocean-atmosphereprocesses in current models are the mainreason for this shortcoming.Hurricanes extract most of their energy fromthe heat stored in the ocean upper-layersthrough the surface heat exchanges. The turbulentmixing induced by wind, waves andcurrents is also an important source of oceaniccooling which has a direct impact on hurricaneintensity.The upper ocean response to the hurricaneFrances in 2004 has been studied using anocean mixed-layer model in the Antillesregion (figure a). The comparison of thesimulated sea surface temperatures (SST)with the satellite SST data highlights astrong cooling on the right side of the hurricanetrack and gives a good validation ofthis model (figure b).The consequences of such an upper oceancooling on hurricanes life cycle will beshortly investigated with a coupled oceanatmospheremodel. 2014 . Research and development: annual report 2007

10°S20°S a - Ground projection of the 26 th of February 2007 at 00 UTC observations :white dots symbolize available observations, black ones those actually used bythe Aladin-Réunion analysis; red crosses locate pseudo-observations whichcorrespond to the cyclone GAMEDE (three-dimensional wind vortex – at 100and 200 km rings and at 10 m, 850, 700, 500 hPa levels – and the mean sealevel pressure at the centre).b - Mean direct cyclone position errors as a function of range of four modelsover the period 29 th January 2007 at 0000 UTC - 15 th March 2007 at 1200 UTCincluding Dora, Enok, Favio, Gamede, Indlala tropical systems. Samples are thesame for every model and vary from 76 to 50 elements depending on therange. The comparison between "Aladin-Réunion 2008", which uses the newcyclone initialization, and "Aladin-Réunion 2007", which does not, illustratesthe benefits of this technique.ababErreur de position (km)1850°E 60°E 70°E250225200175150125100Aladin 200875Aladin 200750Arpege Tropiques(a) Frances cyclone path25CEPMMTfrom 30/08 to 04/09/2004,00 6 12 18 24 30 36 42and comparison (b) of observedÉchéances (h)and forecasted sea surfacetemperature (SST).ab20ab19 a - Vertical cross section of horizontal wind velocity (colouredisosurfaces in m/s) and wind vectors on 22/01/2002 at 2200 UTCat La Reunion Island location, for the experiment “Ocean” in whichthe island has been replaced by the ocean.b - As in figure (a) but for the experiment “Island”,that means with La Reunion Island orography.15 . Research and development: annual report 2007

AmmaAfter the intensive observations periods in 2006, data collectedduring the AMMA campaign were analyzed all along 2007. A firstassessment by the scientific community was made during theKarlsruhe conference in autumn. The first results are very attractive …Use of data collectedduring the AMMA campaignObservationof the Cold Tongueduring the AMMA/EGEEexperimentsEvery year the Gulf of Guinea is the seat ofan intense cooling along the Equator: this isthe well-known Atlantic Cold Tongue (ACT).This signal is well developed in the easternpart of the Tropical Atlantic Basin where thethermocline is close to the surface. This coolingbegins usually in May and the seasonalvariations of the sea surface temperatures(SSTs) reach 5 to 7 °C on average. As soon asthis cold anomaly is formed, its northernboundary is in contact with the warm watersof the northern part of the Gulf of Guinea:this generates important north to south SSTgradients as well as a strong discontinuity ofthe sea surface fluxes.One of the main objectives of theAMMA/EGEE program is to identify themechanisms which set up the ACT and thecoupling processes between the ACT and theAfrican monsoon. The first results obtainedfrom this program concern the strong SST differencesobserved between 2005 and 2006.These two years are very contrasted in termof ACT formation, since the 2005 ACT is theearliest for the past 25 years; conversely the2006 ACT is one of the latest. Moreover, thistime shift can be related to the delay of theAfrican monsoon observed in 2006 comparedto 2005.The analysis indicates that the ACT coolingin 2005 was suddenly increased after astrong and early wind burst, associated withthe trade winds from the southern hemisphere.This event induced an intense mixingof surface waters with colder waters from theupper thermocline south of the Equator. Thecentral Atlantic also experienced strongwinds as early as April 2005, which largelypreconditioned the surface mixed layersover the whole basin.The VHF windprofiler during AMMAcampaignBetween April 2006 and November 2007,the VHF radar which operated on theNangatchori site (Benin), in order to providehigh-resolution observations of the WestAfrican Monsoon.Every hour, this instrument measured thewind profile above its location from 1.6 to10 km height with a 375 m vertical resolution,giving, in particular, a detailed analysisof the African Easterly Jet and of easterlywaves around 4 km height. Together withlow level phenomena observed by the UHFprofiler, these events have a great influenceon the precipitations occurring in the regionand their consequences on agriculture,health and economical issues.Besides, the observation of waves in a verylarge spectral range has given importantinformations on the energy budget and onthe momentum transport, thus bringingcomplementary elements about the largescalecirculation and the structure of theatmosphere which characterize of the West-African Monsoon.Finally, the radar reflectivity and the signalwidth on the spectrum allowed an estimationof the atmospheric turbulence. Extractionof the humidity component from theseparameters has contributed to finely tunethe estimation of the water vapour and tocomplete radiometric measurements.The VHF profiler has given very satisfactoryresults during most of its stay in Benin.Hourly measurements have been systematicallycontrolled and sent to the data base ofAMMA Campaign. They include the threewind components, radar reflectivity and turbulentdissipation rate. The year 2008 willbe dedicated to the scientific exploitation ofthe radar data combined with other remotesensinginstruments installed on the samesite.Humidity biascorrection ofradiosondes duringthe AMMA campaignDuring AMMA SOP, the daily number ofradiosoundings performed over WesternAfrica and transmitted on the GlobalTelecommunication System (GTS) was multipliedby 3, but some sondes showed systematicbiases.The first objective evaluation showed importantdry humidity biases for stations havingused Vaisala RS80 type radiosondes, whichrepresents half of the stations of the AMMAdomain. The station of Niamey (Niger) performed8 soundings / day during the 2 periodsof intensive observations of June,2006 (IOP1, June 20-30, 2006 and IOP2,August 1-15, 2006). During these 2 IOPsVaisala RS92 (good quality) were alternativelylaunched (00, 06, 12, 18 UTC) withVaisala RS80 (03, 09, 15, 21 UTC).The impact of this staggered sampling isvisible in the fig. 1 at Niamey: the dottedline exhibits a serrated shape, where theunrealistic very low values of CAPE correspondto the diagnosis computed from rawRS80 data. A statistically based correctionmethod using the staggered sampling atNiamey is able to diagnose the differentialhumidity bias between the 2 types of Vaisalasondes. This bias is plotted in fig. 2, whereone can see 2 maxima: one in the low troposphere(up to 15 %) and the other one inupper troposphere (above 20 %). The solidline in fig.1 corresponds to the CAPE temporalseries with corrected RS80 data; this firstcorrection produces a much more consistentseries. This method was applied to differentsites and validated with independent coincidentGPS data.After an extensive validation of the methodology,a correction of the whole AMMAdatabase will be performed.1 2 316 . Research and development: annual report 2007

4°N 320°104°S- 12Altitude MSL (km)0 4 8 12 16 20Amma - VHF - Nangatchori : FF (m/s) Evolution of thewind speedmeasured by theVHF profilerbetween 14/06and 23/07/2006.Strong timevariations occurringbetween 2.5 and5 km height areclearly indicated.8°S4°NApril May June July August- 2- 18.6 22.6 26.6 30.6 4.7 8.7 12.7 16.7 20.714.6.2006 00:00 - 23.7.2006 23:59aCAPE400030000°0.04(J.kg -1 )2000100004°S8°S Hovmüller diagrams of the difference between 2006 and 2005 forthe sea surface temperatures (top) and for the wind stress (bottom).Note that SST differences of nearly 3 °C appear soon after a strongwind burst coming from the southern hemisphere in May 2005.Range (km)1512963022 septembre 2006 - Vol 72 - Leg1 FL 25014.2 14.3 14.4 14.5 14.6 14.7 14.8 14.9Time (hour)14.345114.344814.344114.343014.342814.390914.390814.390714.390514.3904Images (capteurs 2DC, taille 25 µm) (images de surface > 0,125 mm 2 )Permet de connaitre l’équilibre entre givrage/aggrégation14.425414.425214.424714.424314.424114.500814.500614.500514.500314.500222.9.2006 H = 14.8600 : 14.87022.9.2006 H = 14.9100 : 14.92022.9.2006 H = 14.9200 : 14.93010.00010.00010.0000 cm-3 µm-11.0000.1000.0100.00- 0.04- 0.0810 cm-3 µm-11.0000.1000.0103b-10001 2 3 4 5 6 7 8 9 10 11 12Day of August 2006T (°C)- 60- 40- 200- 5- 10- 15- 20- 25- 30Distribution dimensionnelledes particulesObservation de spectres bimodauxcaractérisés par des processusde croissance différents(givrage/aggrégation)0.001 0.001 0.00110 100 1000 10 000 10 100 1000 10 000 10 100 1000 10 000Diamètre (µm)Diamètre (µm)Diamètre (µm)0200- 4 - 800 cm-3 µm-120 40 60 80 100RH (%)1.0000.1000.010- 16- 4- 20- 8Nighttime- 124- 12- 8- 8- 4- 4- 20- 16- 12- 8- 4 a - Time evolution of theCAPE computed every 3 hoursfrom radiosounding ascents atNiamey. The solid line is forcorrected data, the dashed linefor uncorrected data. Shadedbackground for night, whitebackground for day.b - Night humidity bias(in shading) of the Vaïsala RS80sondes relative to RS92 sondesat Niamey. The axes aretemperature and relative humidityas observed by RS80 sondes.Superposed dashed linescorrespond to 1 st and lastpercentiles (10 % and 100 %cumulative distribution functionisolines respectively). Saturationline relative to ice has beensuperposed (thin line with dots). Vertical cross-section of radar reflectivity(colours) characterizing the ice content and thesize of particles as observed by the zenith andnadir antenna of the RASTA radar onboardFrench Falcon 20 within a Cb anvil. The otherscurves correspond to microphysics in situmeasurements.%4Observationof anvils duringthe AMMA SOPThe stratiform and cirriform parts formed atthe rear of the convective parts of tropicalmesoscale convective systems last fromseveral hours up to several days. Thesewidespread anvils have an importantimpact at large scale, and may modulatethe monsoon components due to theirradiative forcing.The AMMA Specific Period of Observations(SOP) in 2006 allowed for the 1 st time todocument the internal properties of tropicalanvils by combining remote sensing measurements(radars, lidars) from surface, aircrafts(microphysics, RALI) and from space(CloudSat, CALIPSO). The objective is,through the treatment of those measurements,to document the dynamical, microphysicaland radiative properties of theseanvils and cirrus clouds at different scales,and to evaluate their impact on the complexWest African monsoon system.The exploitation of these data have alreadyallowed to document several anvils case17 . Research and development: annual report 2007studies and the calibration/evaluation ofthe RASTA radar. The comparison of Cloudsatdata with RASTA radar revealed theoccurrence of multiple scattering effects inspaceborne measurements. This result mayhave important implication to quantitativelyexploit the Cloudsat measurements and toelaborate climatologies of cloud properties(Bouniol et al. 2007). 4

5 Time-latitudediagram of ECMWFanalysis precipitablewater (colours inkg.m -2 ), meansea-level pressurefiltered to removediurnal variability(black iso-contoursin hPa) and 925 hPadaily wind (blackarrows in m.s -1 )averaged over0-10 E for 15 Mayto 30 June 2006. Spatial structure of the first variability mode for daily 2 m temperature, calculatedfrom NCEP reanalysis data (1950-2007).6First results from studiesled within the AMMA campaignMonsoon flux pulsationin West Africa:a fine-scale modeof intra-seasonalvariabilityThe establishment of the monsoon flux overWest Africa has not been extensively exploredand previous studies have focused on relativelylarge time-scales (> 10 days) and spatial(> 2°) scales. For the first time, we focus hereon the variability at higher frequency.When the West African monsoon sets in, iterativenorthward excursions of the monsoon fluxare frequent. Quasi-periodic northward excursionsof highly precipitable water are evidentnorth of 14 N in ECMWF analysis (fig. 5). Thesepenetrations last for about two days. They followa maximum of intensity of the heat low(extension and minimum of pressure) and areconcomitant with an intensification of themonsoon flux (fig. 5). Such pulsations are partof the intra-seasonal variability. They are betterdefined at the beginning and at the end ofthe monsoon than during the monsoon itself(when interaction with convection leads to differentcharacteristics). These pulsations arestationary or westwardly propagative dependingon their interaction with easterly waves.The following mechanism is proposed toexplain such pulsations: the development ofdry convection induces an increase of the heatlow and of the relative vorticity and mayexplain such pulsations. This leads to an aspirationof the monsoon flux that brings moistureand which explains the increase inprecipitable water. The monsoon flux alsobrings cooler air which tends to destroy theheat low.Future works will analyse mesoscale simulationsand observations in order to confirmthe proposed mechanisms. Moreover, thefactors that can modulate the characteristicsof such pulsations will be explored.5Variabilityof the African Heat Lowand its link withmid-latitudesIn the frame of the AMMA project, a particularregard has been devoted to the Saharian thermaldepression (Heat Low), especially duringthe 2006 summer measurement campaign.The climatic approach of the phenomenonallows to replace the 2006 season among thelast 50 years seasonal observations.By using an Empirical Orthogonal Functionmethod on the daily datas from NCEP andECMWF reanalyses, we identified a robustmode of variability of the 2 m temperatureover North Africa. This mode presents a characteristictime of 20 to 30 days and an East-West dipolar spatial structure, opposing thecoastal Morocco and Mauritania region withcentral Libya (see figure).By isolating the successive maxima andminima during the 58 last years (1950-2007), we reconstructed the global dailyatmospheric fields leading the extrema ofthis mode. These composite fields show arelation between the Heat Low and mid-latitudeconditions. Indeed, the 4 summer weatherregimes established by CERFACS, whichare equally distributed in average, are fairlywell discriminated when Heat Low phasesare considered. The positive phase (colderwestern part) corresponds, in 75 % of thecases, to a blocking or NAO- regimes whilethe negative phase corresponds to NAO+ orAtlantic ridge in the same proportions.Knowledge of the links between Heat Lowand weather regimes may allow an increaseof the prediction potential in this region,particularly if, in the same time, the role ofthe Heat Low in the monsoon behavior isassessed more deeply. 6Validation of convectiveparametrizationschemes on westernAfrica with theALADIN-CLIMAT modelIn large-scale models, mean effect of convectiveprocesses on a grid-mesh is computed ina simplified representation called convectiveparametrization. The behaviours of differentconvective parametrization schemes availablein the global ARPEGE-CLIMAT model arestudied, focussing on western Africa.Then, comparisons are made between finemeshsimulations in which convection isexplicitely computed (non-hydrostatic Méso-NH simulation with a 5 km horizontal gridmesh)and simulations run on the samehorizontal area, with the same initial andlateral conditions, with the ALADIN-CLIMATLimited Area Model (LAM), in which convectiveprocesses are parameterized. The caseunder study is that of a squall line observedon western Africa in August 1992 during theHapex-Sahel experiment.The results obtained in an ALADIN-CLIMATsimulation with a 125 km horizontal gridmeshexhibit the different behaviours of thetested parametrization schemes and theimproved precipitation pattern obtainedwith some of these schemes. Developmentof relevant diagnostics and tests on thehorizontal grid-mesh used in the LAM areplanned, before applying the methodologyto cases observed during the AMMA fieldexperiment (summer 2006).These studies participate in improving currentand under development parametrizationschemes. 718 . Research and development: annual report 2007

7RR−Conv (mm/h) + MOCON + vent 700 hPa− (21−08−1992/00 h)HX125 / ECH = 18 h5˚10˚20˚20˚11RR−Conv (mm/h) + CAPE (J/KG) + vent 700 hPa− (21−08−1992/00 h)HX125int / ECH = 18 h5˚10˚20˚600000050006000700030004000110100020003000400050007000600050003000200015˚22321112332122115˚10003000200040005000600070003000400050006000700 070004000500 060003000400020003000400015˚ a) Explicit precipitation field simulatedwith the 5 km horizontal grid-meshmodel over western Africa (colours).Arrows: winds at 650 hPa. 21 August1992, 18 UTC.b) Convective precipitation field(colours) and winds at 700 hPasimulated with ALADIN-CLIMATover the same domain. Standardversion of the physical package(ARPEGE-CLIMAT V4).Convection triggering is determinedby the parameter described bythe red isolines.c) Convective precipitation field(colours) and winds at 700 hPasimulated with ALADIN-CLIMATover the same domain. Improvedversion of the physical package.Convection triggering is determinedby the parameter described bythe red isolines.ab10˚421311211231231233410˚5˚10˚5˚10˚1.5 4.0 0.0 0.5 1.0 2.0 3.0 8.0 0 1 2 3 4 5 6 7 88700030 00600040002000500080003000700060004000200050001000300020006000400010005000300020006000400010005000100030001000200020010˚c Comparative maps of visible albedos for MSG (top left) and MODIS (top right) for the period from 12 to 26 July 2006 for the AMMAzone. The magnitude of relative errors (bottom left) is explained by the relative bad/good ? quality of MODIS product (bottom right).The SAF programme on Land Surface Analysis:an operational production extended to AfricaThe SAF (Satellite Application Facility) programmeon Land Surface Analysis (LSA) producesoperationally surface variables from theobservations of MSG and EPS EUMETSATsatellites. LSA SAF is placed under the controlof EUMETSAT who gave responsibility for pilotingand for the production to the Institute ofMeteorology of Portugal. The consortiumencompasses 8 cooperative entities with 4representing National Meteorological Services(Belgium, Finland, France, Portugal). The projectwill move into its operational phase inMarch 2007.The project includes 5 types of products (operational,internal operational, candidate operational,demonstrative, experimental) generated atthe nominal spatial resolution of MSG.Operational products only are available forpublic access over the MSG disk (www.landsaf.meteo.pt).They are the albedo, the surfacetemperature, the short-wave and long-waveradiation fluxes, and the snow cover.CNRM is responsible for albedo and down-wellingsurface short-wave radiation flux. Their validationis achieved through a comparison within situ measurements and equivalent satellite19 . Research and development: annual report 2007products. As for Europe, this latter was extendedto spatial domains, the kriging networkRADOME for radiation flux and MODIS imageryfor albedo. An utilization of the albedo withinSURFEX was initiated. An special effort wasmade for a validation over Africa, taking benefitfrom in situ data from the AMMA programme.In 2008, it will consist to initiate the mergingbetween MSG and EPS data, with, as a firstgoal, to extend the geographic coverage tohigh latitudes for all products, and to combineoptimally the geostationary and polar observationsfor albedo over the MSG disk. 8

MeteorologicalprocessOne cannot understand and forecast meteorological processwithout an excellent knowledge of the atmospheric mechanisms.All along 2007, works on cyclogenesis went on, some significantprogress were made around carbon cycle modelling, …Cyclogenesis and previsibility studiesCritical regions of upper-troposphericdisturbances regenerationMid-latitude synoptic-scale anomaliesappear in the upper troposphere and evolvealong the jet streams. These upper-troposphericanomalies are usually strongly stretcheddue to the action of the deformationfield of the jet along which they evolve, leadingto a loss of their energy. However, thesame anomalies can be temporarily regeneratedif they cross the jet. Jet crossing occurspreferentially in specific points along the jetaxis, called critical points, as shown by thefigure.In each figure panel, the same green triangleappears. It is a remarkable point of the jetand more precisely it is a saddle point of anew key field called effective deformationwhich is represented by its positive values inlight red shading. Two simulations using abarotropic model on the sphere are compared,one with all the terms (the nonlinearcase) and the other with linear terms only(the linear case). In the nonlinear case, theperturbation is first strongly stretched on thesouthern side of the jet, then it crosses thejet around the critical point. At this moment,the perturbation is characterized by acontraction stage leading to an increase ofkinetic energy. In the linear case, the perturbationremains on the southern side of thejet, it does not cross the jet and it keepsstretching which results in a strong loss ofkinetic energy.To conclude, the underlined mechanismdepends on the combined effects of the effectivedeformation and nonlinearities and is notrelated to any linear instability. 1Towards an objective methodto define humidity anomaliesSynoptic-scale depressions can be describedwith the potentiel vorticity field, thatsummarizes all the dry dynamical aspects,and a field that quantifies humidity.Whereas moisture is classically consideredas modulating the growth of North-Atlanticdepressions, the effect of water –more preciselyits phase changes– on Mediterraneanstorms seems to be much more central. Adescription aiming at a better understandingof the evolution of these synoptic systemsmust therefore include informationabout moisture.Newly defined methodologies at CNRM,namely wavelet decomposition for extractingtropopause folds, have been extendedto humidity fields: specific or relative humidityor even other derived fields. Finding allthe anomalies in a field requires two steps:firstly, the large-scale environment shouldbe separated from all the anomalies, each ofwhich has then to be isolated from theothers. The first step has been refined inorder to relax some assumptions made onthe anomalies properties, that hold forupper-level potentiel vorticity but are notrelevant for moisture fields. This leads toadd a small portion of the large-scale of thetotal field to the small-scale in order to buildthe "anomalies" field.In the near future, effort will be made to usethis field to define individual anomalies. 2The wavelet extractionimproves the coherenceof potential-vorticitystructuresMid-latitude storms often result from theinteractions between a low-level vortex andan upper-level one. The inversion of potentialvorticity provides a technique to attributethe meteorological fields (wind andtemperature) to each vortex, and to studytheir interactions. The results depend on thetechnique used to extract these vortices. Weshow hereafter that the new objectivemethod of extraction based on wavelettheory gives a structure that is more coherentin time than the more classical and subjectivemonopolar extraction.If an anomaly is extracted at some initialtime, its evolution may be predicted as thedifference between the simulation with theinitial anomaly and the simulation withoutit. The result is a predicted anomaly. At thesame final moment of the forecast, anotheranomaly may be extracted from the predictedtotal field. If the anomaly interacts onlywith its environment, both anomalies mustbe similar. This criterium is a way to assessthe performance of the extraction. From thefigure, it is obvious that the wavelet anomalies,predicted and extracted, are quite similar,which is not true for the monopolaranomalies, which is much dispersed by themodel simulation. This property makes thewavelet extraction preferable for the study ofthe interactions leading to storms and alsofor its numerical applications. 320 . Research and development: annual report 2007

170 Nonlinear (left) and linear (right)evolution of a synoptic-scaleperturbation moving alonga jet with a critical point representedby a black triangle about 25° W, 54° N.Upper and lower panels correspond to 36 hand 48 h after the initial time. Blue contoursare the jet wind speed isolines (interval:10 m/s for values greater than 20 m/s).Light red shading, black arrows and heavyblack isolines represent respectively regionsof positive effective deformation(interval: 5 10 -10 s -2 ), the dilatation axesand the perturbation vorticity(interval: 2.5 10 -4 s -1 , dashed and solidcontours for negative and positive values).20303020Non linéaire, T = 36 hLinéaire, T = 36 h30-50 -40 -30 -20 -10 0 -50 -40 -30 -20 -10 0702030302050502030302020303020Non linéaire, T = 48 h30Linéaire, T = 48 hab Several decompositions of thespecific humidity field at 850 hPa,01/12/2001, 00 UTC,contour interval : 1g/kg.(a) total field (blue below 10g/kg,red above 10g/kg);(b) 8-day high pass filtered fieldcomponent (blue below -1g/kg,red above 1g/kg);(c) small scale wavelets componentof the field (same contouring as in b),(d) the set of all anomalies extractedwith the fully extended algorithm(same contouring as in b).2cd Coherence between the predictedanomalies (left) and the extracted anomaliesat the same time (right) for the waveletextraction (top) and for the monopolarextraction (bottom). The study focuseson the upper-level vortex associatedwith the 27 December 1999 storm.The initial extractions are made fromthe fields on the 27 th at 06 UTC, and fromthose in the 6 h forecast so thatthe final extractions are made on the 27 that 12 UTC. The shown fields are:the relative vorticity of the anomalyat the 350 hPa level (interval 5 10 -5 s -1 ,positive in orange shading, negative in blueshading), and the geopotential of itsenvironment at 350 hPa (interval 20 damgp,bold line). With the wavelet method,the anomaly are more coherent thanthe monopolar one.321 . Research and development: annual report 2007

4Routine20 juin 2007 à 21 h TU Top chart.Blue shading: areas of need calculated forthe case of 2007 June 21 at 00 h UTC,taking into account both the sensitivity ofthe forecast to its initial conditions and theuncertainty on the guess;Red shading: same sensitivities plus thatto the analysis of routine radiosoundings(RS). These areas are valid 15 hoursbefore the event (forecast valid for June21 at 12 UTC in the region shown with adotted circle).Obs.débutObs.milieuObs.fin20 juin 2007 à 21 h TU 21 juin 2007 à 00 h TU 21 juin 2007 à 03 h TU Histogram.Prediction of the error variance reductionfor the function with respect to which thesensitivity calculations were performedand due to the addition of the adapted RS(% of the reduction induced bythe assimilated routine network againstthe first guess). These added RS weredeployed with a variable delay withinthe assimilation time window, as shownin the legend of the histogram (middleand end, respectively).Réduction de variance d´erreur (%)40.7838.8436.8934.9533.0131.0629.1227.1725.2323.2820 juin 2007 à 21 h 21 juin 2007 à 00 h 21 juin 2007 à 03 hobs.début obs.milieu obs.finDate de référence : 21 juin 2007 à 00 h TU Bottom charts.Areas of residual need resulting from theassimilation of the extended network:routine RS plus additional RS drawnin the same colour (orange, greenor purple) and with the same name(obs.start, obs.mid or obs.end) than onthe histogram. The valid time is givenon the figure. Dashed red contours depictthe areas where uncertainty is reduceddue to the extended network.Prediction of the benefit of optimally located observationsAdaptive observation consists in the additionof observations in so-called sensitiveareas computed to improve (locally) a numericalweather prediction. Linear techniques(using adjoint calculations) have been designedto investigate the sensitivity of forecaststo their initial conditions (ie. analysis,or the observations being assimilated tocompute the former).To design the most profitable deployment ofadditional observations, a quantitative tool isused in ARPEGE that compares the expectedbenefits from a variety of simulated additionalobservation networks (see histogram onthe figure). The method (called KFS) computesan estimate of the uncertainty residingin the analysis (which is the initial conditionsof the forecast of interest). Part of the codecomes from ECMWF.The national CYPRIM project focuses on largescale aspects of Mediterranean cases representativeof heavy rainfall events. The firststeps of the KFS computation deal with theroutine observations only. These results maybe used to design the extra deployments tobe evaluated during the last steps of the KFS.The figure shows the expected benefit ofthree deployments (10 soundings each, all22 . Research and development: annual report 2007simulated, displayed on the histogram). It furthershows the zones of needs where theaddition of these observations is likely to bebeneficial to the quality of the forecast. Thisshows a June 2007 case, using only TEMP(radiosoundings, RS) observations. The locationsof the 3 deployments are similar, theydiffer primarily by the deployment time:either early (case shown), middle or late inthe 4D-Var assimilation time window. Thelatest deployment promises the highestimpact, which is consistent with the 4D-Vartheory. 4

Vertical cross section of the vertical velocity (in m.s -1 )after 3000 s integration for orographic trappedwaves induced by the hill in a west to east flow.On the left with the previous/former advectionschemes, on the right with the new ones.6 0005 4004 8004 2003 6003 0002 4001 8001 2006 00(min : -0.445E + 01, max : 0.590E + 01)2.0001.8001.6001.4001.2001.0000.8000.6000.4000.2000.100-0.100-0.200-0.400-0.600-0.800-1.000-1.200-1.400-1.600-1.800-2.00000 6 700 13 400 20 100 26 800 33 500WWT m/sTime = 3 00065 Sensitivity experiments to the low-level flow speed:Cold pool (virtual potential temperature in colour scale, K), 24 h accumulatedprecipitation (purples lines: 50, 250, 500 and 750 mm; the maximumis indicated), updrafts (red areas, > 1m/s) and downdrafts (yellow areas,< -0.5m/s) at 1000 m, wind vectors at 10 m (black arrows, m/s) after48 h for the reference simulation (REF) and for the experiences of sensitivityto the wind speed of the low-level flow with a slower jet (WIN10)or a faster one (WIN20). The relief is represented in grey scale above 500 m.Meso scale eventsA new advection scheme for Meso-NHMeso-NH, is a research model used to simulatereal and academic mesoscale flows,with a scale resolution currently rangingfrom 50 km to 10 m, which, until now, usedstandard transport algorithms, associatedto a “leap-frog” time stepping scheme. Butthe drawback was a strong time step limitationwhich prevented getting accurateresults. Therefore, one major objective wasto increase the time step of Meso-NH with ahigher quality advection scheme.A new Eulerian advection scheme has beensuccessfully implemented for scalar variables,associated with a “forward in time”temporal scheme for the advection termsand a fourth order centred advectionscheme for momentum. The impact is highlypositive in terms of accuracy and stability(figure). But the increase of the time stepshould become more efficient once the“leap-frog” temporal scheme will have evolvedto a new temporal scheme for the overallmodel. 5Idealized modelling framework for quasi-stationary convective systemsSouth-eastern France is prone to heavy precipitationinduced by quasi-stationarymesoscale convective systems. An idealizedmodelling framework has been set-up inorder to study the sensitivity to low-levelconditions on the location and the intensityof these systems.Atmospheric simulations are performedwith the MESO-NH research model at 2.5 kmfor an idealized moist unstable flow, andusing real topography. Thus, an unstablelow-level jet pointing towards the Cévennesis imposed.The reference simulation succeeds in simulatinga quasi-stationary convective system.Precipitations spread from the Sea to theMassif Central. The evaporation of part ofthe (falling) precipitation induces a coldpool under the system. The low-level jetimpinges the leading edge of this cold pool,inducing upward motions that trigger newconvective cells.The characteristics of the low-level flow overthe Sea (humidity, wind speed, instability)are varied. The figure shows the sensitivityto the wind speed: the slower the flow, themore upstream the system is located. Also,the drier the environment is or the more unstablethe flow, the more upstream the systemis located. Different lifting mechanisms23 . Research and development: annual report 2007compete to explain the specific location ofthe systems (orographic forcing, cold pool,low-level convergence due to relief).In future work, we will continue to explore thepredictability associated to these systemsthrough this idealized framework by investigatingmore systematically the low-level conditions;the impact of the relief and theMediterranean Sea will be assessed too.6

The programme ECOCLIMAP-II:a new land cover classification over EuropeThe ECOCLIMAP programme encompasses aland cover classification and a database ofsurface parameters inferred from the classificationbased on look-up tables.A new classification of the vegetation inareas thematically and functionally homogeneoushas been achieved over Europe. Theinitial classifications are Corine2000 at100 m for most of the domain and GLC2000at 1 km (Global Land Cover 2000, 1 year ofSPOT/VEGETATION data) for the rest of thedomain. They have been split, based on anautomatic classification, considering 7 years(1999 to 2005) of data of the vegetationindex SPOT/VEGETATION with a disregardthis time to climate zoning. This has led to273 classes. The criteria account for independentfactors from vegetation cover likethe climate or the agriculture modes imple-mented at the regional level. An independentvalidation considered the statistical datasets issued from agricultural practices inFrance.The classes are disaggregated in one or severalfractions of vegetation types from ISBA.This work relies in the new version on thesearch of pure pixels at 1 km of a vegetationtype. The variable to disaggregate is the leafarea index, which is less contaminated by soileffect than the vegetation index. The leaf areaindex and albedo are the more relevant variablesof ECOCLIMAP. In the new version, theyare derived from the combination of the 1 kmproducts MODIS and VEGETATION (Europeanproject CYCLOPES).The follow-on of this work is the implementationof test cases in SURFEX in order to assess theimpact of the new database ECOCLIMAP. 7Spatial variation of atmospheric CO 2 :the CarboEurope RegionalExperiment Strategy CERESContinental carboncycle modellingA new option of the CNRM land surfacemodel, ISBA (Interactions between Soil,Biosphere and Atmosphere) was developedin order to represent the terrestrial componentof the carbon cycle. The new model,referred to as ISBA-CC (Carbon Cycle) simulatesthe main carbon fluxes exchanged betweenthe continental surface and theatmosphere (photosynthesis, autotrophicrespiration and heterotrophic respiration),as well as the stocks and the fluxes of carbonin the vegetation and in the soil.The model was validated for 26 sites of theFLUXNET network located at middle and highlatitudes of the Northern Hemisphere, whichprovide measurements of energy, water andcarbon fluxes. The model reproduces wellthe main properties of the diurnal andannual cycles, as well as intra-seasonal andinter-annual variability. It also favourablycompares with other terrestrial carbonmodels, among which the ORCHIDEE modelof IPSL.The ISBA-CC model will further be coupledwith the general circulation model of CNRM,ARPEGE-Climat, along with the other componentsof the carbon cycle, to simulate thefeedbacks between the carbon cycle and theclimate. 9A methodology to simulate the spatial variationof CO 2 within the Atmospheric boundarylayer (ABL) based on observations has beendeveloped during the CarboEurope RegionalExperiment CERES. This year, a lot of effort hasbeen devoted to the numerical interpretationof the data collected during the CERES 2005field campaign.Five atmospheric meso scale models, includingan interactive simulation of CO 2 betweenthe surface and the atmosphere, have beenevaluated against a large variety of data (figure8): flux of CO 2 close to the surface, ABL diurnalevolution in the Landes forest, spatial variationof CO 2 in the ABL as observed by the PiperAztec instrumented aircraft. The 5 meso scalemodels showed a good ability to simulate CO 2assimilation over a wheat field (a). However, alarge scatter was found in the simulations ofCO 2 observed by the aircraft within the ABL (c)as a result of large differences noted in thesimulation of the ABL evolution (b).Two new experiments have been conductedduring April and September 2007 in order tosample different meteorological conditions andcrop developments. 824 . Research and development: annual report 2007

Land cover classificationECOCLIMAP-II overEurope with 273 classes.78 An inter comparison of 5meso scale atmosphericmodels against observationscollected in June, 6 duringCERES 05:(a) comparison withobservations of CO 2over a wheat field,(b) with the vertical profileof potential temperatureobserved withinthe Landes forest(c) with the variation of CO 2in the ABL monitoredwith/by the instrumentedPiper Aztec aircraft.abc9Corrélation au carré - NCARB CENT - LE (moyennes mensuelles)1.00.8r2 (-)0.60.4Square correlations between the monthlymeans of the latent heat flux (LE, top) andof the net carbon flux (NEE, bottom) measuredin 26 FLUXNET sites and simulated by ISBA-CC(blue circles) and by ORCHIDEE (red diamonds).r2 (-) HE HV SO VI WB FL HY NO AB BR BX LD ME TH WE SKo SKy CP PO BVS BVC UP LW SHCorrélation au carré - NCARB CENT - NEE (moyennes mensuelles)GU HE HV SO VI WB FL HY NO AB BR BX LD ME TH WE SKo SKy CP PO BVS BVC UP LW SH25 . Research and development: annual report 2007

Taux de détection100806040200-0,5-1-1,5H + 1SIRSIR_ASSIR_RECAL00 20 40 60 80 100Taux de fausses alertesValeur économique Ve0,10,80,60,40,2H + 1SIR_BRUTSIR_ASSIR_REC0,00,0 0,2 0,4 0,6 0,8 100Alpha ROC diagrams (left) and cost/lossdiagrams (right) for the first hourlyforecast and for each models:brut model (SIR_BRUT), model withstatistical adaptations (SIR_AS)and model with in situ measurements(SIR_RECAL). For SIR_RECAL andthe 0 °C threshold, we obtain a hit rateequal to 90 %, a false alarms equalto 10 % and a great economic interestof the model for small cost/loss ratios.10Evaluation of a numerical modelfor the simulation of surface temperatureinstalled for “Aeroports de Paris”Thanks to a great collaboration between ADPLABO and the Studies Department of Météo-France in Paris, a numerical model for thesimulation of surface temperature over twotaxiways of PARIS-CDG airport was tested.This model was used with predicted data(from the ARPEGE French meteorologicalmodel) in order to evaluate its behaviour inoperational conditions. In particular, it wastested during the 2004-2005 and 2005-2006winters on the taxiways of Paris-CDG airportthanks to the in situ measurements from ADPLABO. In order to evaluate the so-called SIRmodel in operational conditions of uses, themodel was run in real time with predictedatmospheric data, and real time road temperaturemeasurements during the 2006-2007winter.Two different ways of evaluation were investigated.The first one was done through simpleFor some meteorological situations, on therunway of Nice airport, sudden wind shifts areobserved, turning abruptly from a western toan eastern sector, or conversely. This phenomenonstrongly disrupts the air traffic controlof Nice airport and leads to turbulences thatcan be dangerous for aircrafts.A first study was conducted using the mesoscaleresearch model MESONH, with a 500meters mesh version, on a representative dayof this phenomenon. By comparing the verticalstructure of the predicted winds and thediverse available observations (low layers andplane soundings), we notice that MESONHsucceeds in representing a phenomenonrather alike the one that occurred, but not atthe right location (a gap of about 20 kilometersfor the eastern wind zone) and with a wrongtiming (4 hours in advance for Nice). We thenstatistics scores, such as Root Mean Square,bias,… for each hourly time step. With a negligiblebias, a good RMS for the first 6 hourlyforecasts (between 0.5 and 1.5 °C) despite adecrease of up to 2 °C for the 24 h forecast,the global results are satisfactory. The secondway to evaluate the numerical model is to testits interest for frozen soil risk management.For each hour, contingency tables associatedwith hit rates and false alarms are producedwhich give an estimate of the economic valueof the model as a function of cost/loss ratio.This one largely depends on the user needs.By the way, the curves that were obtained givean idea of the interest of the model. The benefitsseem important for the 6 first hours forecast,and decrease progressively when theforecast term increase. Nevertheless, it seemsto be a good first step for using such a modelas a help for frozen risk management. 10Mesoscale studies of wind shiftsover the Nice regionused a prototype of the AROME model, whichwill become at the end of 2008 METEO-FRANCEoperational mesoscale model (2,5 kilometersmesh). Nine globally similar meteorologicalsituations over the Nice region were simulated,some leading to wind shifts on the airport platformand some not. In a majority of the treatedcases, the opposition streams zones are realistic.The location of the wind shifts is not alwaysprecise, but we do think that the AROME modelmight drag the forecaster’s attention to a possibleoccurrence of the phenomenon more efficientlythan ALADIN, the current operationalmodel.At the end of 2008, the AROME model willbenefit from a specific observations analysis.We expect further improvements of the forecastof the Nice wind shift phenomenon. 11Three-dimensionalmeasurements of stablestratified turbulenceAtmospheric turbulence is often subject tonegative buoyancy effects due to a stableatmospheric stratification. Although theeffect is globally stabilizing, the resultingdynamics and structure are still only partiallyelucidated due to the complexity of the phenomenaand to the difficult access to fullyturbulent regimes by either direct numericalsimulations or laboratory experiments.In this situation in particular, the effects ofviscosity become important quite rapidly. Inthe laboratory (wind-tunnels, hydraulic tanksor flumes) recently developed non-intrusiveoptical methods make possible the measurementof two-dimensional turbulent velocityfields. However, in the fully turbulent regimesof interest in stratified environments, thesetechniques have not been applied due to thestrong variations in optical indices of refractioninherent to the density stratificationwhich significantly distort the optical paths (asimilar problem is also encountered for earthbasedtelescopes).Another challenge is to be able to measurethe three-dimensional velocity field to betterdescribe and understand the three-dimensionaland anisotropic dynamics. It also enablesdirect measurement of the Lagrangian dispersion,crucial for modelling dispersion ofgaseous pollutants (for example aircraftwakes).For this purpose, a rapid three-dimensionalparticle image velocimetry (PIV) techniquewas developed in collaboration with IMFT(Toulouse) and researchers in the USA, whicheliminates the index of refraction problemsand yields time-resolved three-dimensionaland three-component velocity field measurementswith a spatial resolution as good asthe two-dimensional technique. One suchexample in a regime which is still highlythree-dimensional and turbulent is shown infigure. 1226 . Research and development: annual report 2007

11 MESONH predicted 10 meters windon 12 march 2005 at 13.30 UTC(wind speed in m/s). The wind shiftphenomenon is realistically simulated,but with a gap in space and time patterns.12 Uvelocity field measured in a stratified turbulent flow27 . Research and development: annual report 2007

Climate andclimate changes studiesThe 4 th IPCC report published in 2007 made medias and governmentsaware of the large scale climate changes already observed,or which should happen by the end of this century. Meteo-Francescientists remained very active in this area, and worked mainly onregional climate forecast, extreme events, links between tropicaland extra- tropical climate and much more…Development of CNRM’scoupled global climatemodelThe IPCC fourth assessment report (2007) wasbased on global climate simulations performedby about 20 research institutes. CNRMwas able to participate to this project by usingCNRM-CM global coupled model. This modelconsists of Arpège-Climat AGCM, OPA OGCM,Gelato sea ice model and Trip river routingmodel.This complex coupled system is constantlyimproved and tested. In 2007, the 1860-2000period was simulated with an updated versionof CNRM-CM, in which ocean-atmosphere heatexchanges were better represented. More over,the effect of atmospheric sulphate particles onclimate was considered in a more realistic way.In contrast with greenhouse gases, these particlestend to cause a cooling of the ocean andland surface, which can be particularly strongon the regional scale. Other simulations for thesame period were run, in which land usechanges were taken into account. Morerecently, the impact of volcanic eruptions wasintroduced in Arpège-Climat under the form ofparticles in the lower stratosphere, allowing tosimulate the Pinatubo event (1991) more realistically.This improved version of CNRM-CM was adaptedto run on Météo-France’s new supercomputer,and will allow to perform severalIPCC-like climate simulations within ENSEM-BLES European project by early 2008. Then,CNRM-CM will experience deep changes until2009, in order to account for the most recentupdates of its different components.New couplings will be introduced with the carboncycle, ice sheets and atmospheric chemistry,in order to obtain an even more realisticearth system model. This next generationmodel will serve as a tool to contribute to thenext IPCC set of climate simulations. 1Tropical cyclogenesisindices in the IPCC AR4simulationsFuture evolution of tropical cyclonic activity isof major importance for the scientific communitybut its uncertainty is so high that the latestIPCC report could merely state the lack ofconsensus on this topic.For some time now, methods have been developedin order to measure the probability oftropical cyclone formation in climate models.One of these models was finalized at CNRMfrom existing indices largely used by the scientificcommunity. The refinement that we introducedin the calculation consisted in gettingrid of the 26 °C sea surface temperature (SST)threshold which accuracy whose relevance forthe actual climate will become questionable inthe future.We calculated our index for 15 out of the 19 A2scenarios (among the most severe ones) performedin the frame of the IPCC. Models reproducea realistic global distribution of theobserved index despite some marked biases.When assessing the future climate, answersdiffer greatly from one model to another, somuch so that no conclusion can be drawnregarding the sign of the tendency. This highspread among the models can also be found inthe spatial structure of the SST anomaly calculatedby the different simulations.Several years will probably be needed before areliable tendency can be deduced for the tropicalcyclonic activity. Concerning our work for2008, we will implement a new set of simulationswith the ARPEGE/Climat model in whichwe will prescribe the SST anomalies from thedifferent IPCC simulations; the underlying ideabeing to measure the part of these anomaliesin the spread of the responses. 2Tropical influence onextratropical variabilityThe IRCAAM project, funded by the FrenchNational Research Agency and coordinated byCNRM, mainly aims at understanding if andhow the inter annual and/or intra seasonalmodes of atmospheric tropical variabilitycontrol the extra tropical climate, particularlyover Europe and the Mediterranean basin. Inaddition to statistical analysis, the project isbased on original numerical experiments inwhich the tropical dynamics of the globalArpège-Climat model is controlled through a3D nudging towards the ERA40 reanalyses.Though highly idealized, such experiments arenot disconnected with the issue of long-rangedynamical forecasting. The ultimate objectiveis to assess to what extent improved forecastswithin the Tropics (where the persistence ofsea surface temperature - SST - anomalies ismaximum) could also increase skill scores inthe mid-and-high latitudes. The first case studiesachieved for the boreal summer seasonshow encouraging results (see figure).They show that inter annual anomalies in tropicalcirculation are likely to drive planetarywaves that can propagate polewards and thusmodify in a realistic way (i.e. in agreement withatmospheric analyses and observations) theextra tropical circulation simulated by theArpège-Climat model. 328 . Research and development: annual report 2007

Global mean ocean temperature. HadISST observationsprovided by UKMO/Hadley Centre (black curve).IPCC-AR4 simulation by CNRM-CM3.1 (blue).Simulation by CNRM-CM3.2 (green).Yellow, orange and red: same model, but withland use changes and different ocean initial conditions.1Température de surface de l’océan (°C)19.51918.51817.517Océan global20C3M/Commit20C3M+Aer2OC3M+Aer+L.use 12OC3M+Aer+L.use 22OC3M+Aer+L.use 3Had.C.Data16.51860 1880 1900 1920 1940 1960 1980 2000Années Computation of tropical cycloneformation probability for the ERA40 reanalysis.2 3JJAS 1997-clim V200 (m/s)ERA40No nudging/obs SST R=-0.03ab Observed (a) and simulated (b,c,d) 200 hPameridional wind anomalies averaged between Juneand September 1997. Three ensembles madeof 30 simulations are compared:b) control experiment without nudgingand driven by observed SST,c) experiment nudged within the Tropicsand driven by climatological SST,d) experiment nudged within the Tropicsand driven by observed SST. R is the spatial correlationbetween observed and simulated anomalies northof 30° N. Green contours show the 1971-2000climatology of the 200 hPa zonal wind (differentfor the experiments with and without nudging).Tr nudging/clim SST R=-0.60Tr nudging/obs SST R=-0.71cd-4 -3 -2 -1 1 2 3 429 . Research and development: annual report 2007

52010520510555510a Ratio between the numberof summer heat wave days(number of days when temperatureis 5 °C above normal for more than5 consecutive days) for 2021-2050and the corresponding number inthe reference period 1961-1990.Scenarios A1B (a), A2 (b) and B1 (c).bc530°40°50°7 6 5 4 3 2 150°40°30°50°540°40°22552551054350° 0°10° a : map of the warming en °Cb : drying in mm/d for the end of the 21 st century (2070-2099 period versus 1961-1990)in summer (June-July-August)20°30°30°Indices of extreme events over France in the latestregional scenarios 2021-2050The IPCC 4 th assessment report has requiredcoupled ocean-atmosphere simulations thathave enabled to produce a third generation ofregional scenarios for France. After doublingcarbon dioxide experiments (late 1990 s) andA2 and B2 scenarios of Gicc programme (early2000 s), a new set of three scenarios A1B, A2and B1 has been made recently available. Forthe first time, these simulations address thequestion of the climate for the first half of the21 st century.For the forthcoming next decades, the mainconcern is not a moderate mean warming, butthe evolution of the frequency of extreme phenomena.From the above mentioned threeFollowing the last two IPCC reports (2001,2007), the Mediterranean area has been pointedout as one of the main “hot spots” for a climatechange during the 21 st century. Thevarious global climate models also agree verywell about that area. This leads to robustresults concerning the general warming anddrying of the Mediterranean basin. Thesechanges will be stronger in summer.To obtain high-resolution information aboutthe climate change in this area, the CNRM hasbeen developing for some years a high-resolutionregional version of the ARPEGE/OPA coupledmodel. This Atmosphere-Ocean RegionalClimate Model (AORCM) is the first modelwhich takes into account the air-sea couplingat high resolution for the Mediterranean area.The two coupled models are ARPEGE and OPAas for the CNRM-CM3 IPCC global models buttheir spatial resolution over the area of interestsimulations at 50 km resolution over France, wehave estimated the frequency of summer heatwaves (figure 4), the intensity of heavy rainfalland the duration of dry spells for the period2021-2050. Amidst the spread of model responseswhich result from the unpredictableinter-annual variability, three characteristic featuresarise, which were emphasized for the endof 21 st century in Imfrex: increase in heat wavesand droughts, paradoxical increase (sincemean precipitation decreases) in intensity forthe events above 20 mm/day.Studies on these data will carry on, in order toupdate the results about strong winds and surfacehydrology. 4Climate change simulationof the Euro-Mediterranean area using a dedicatedatmosphere-ocean regional climate modelis enhanced to 50 km in the atmosphere andto 10 km in the sea. A 140-year simulation(1960-2099) has been carried out with themodel following the A2 SRES hypothesis forthe 21 st century.A high-resolution description of the warmingand drying of the Mediterranean and southernEurope area is obtained thanks to the simulation(figure a). This model also allows to quantifythe warming, saltening (figure b) and sealevel rise of the Mediterranean Sea. The futureof the Mediterranean regional coupled climatemodels will take place in the European CIRCEproject with the inter-comparison of 6 differentAORCMs. This will lead to a better assessmentof the climate change uncertainty range for theMediterranean basin.These AORCMs are also seen as key numericaltools in the framework of the future HyMExproject. 5Heavy precipitationMediterranean eventsin a future climate,a preview…The national CYPRIM project, started in2005, provides a multidisciplinary frameworkaimed at heavy precipitation events(HPE) studies. One objective of CYPRIM is toassess the evolution of the related hazardlinked with the climate change. The worksummarized here is a better identification ofthe present climate and the development ofan objective automatic detection of suchevents for future climate simulations. It hasbeen achieved through a collaboration between3 CNRM sections within 3 differentgroups.The main task has involved combining rainfalldata from the Météo-France network togetherwith a reference data bank of weather fields(ERA40) obtained at ECMWF. A set of 1210significant precipitation events has been collectedand their large-scale environment havethen been constructed using statistical automaticclassification algorithms. This yieldsweather patterns related to the various zonesof the average climatology of rainfall in thearea. A close look at the statistical relationshipreveals that only 2 weather patterns arelinked to HPE. The meteorological ingredientsthat characterize HPE can then be highlighted.They lead to an algorithm that enables todetect favourable conditions that can lead toHPE from the dynamical information alone.The number of cases detected does notchange much between now and the end ofthe century (A2 emission scenario). In thefuture climate composite of HPE, only thewarm moist influx seems to take a more systematicpreferred south westerly orientation(see figure).High resolution simulations of present andfuture climate cases will allow detailed examinationof possible evolutions of the localrainfall amounts or of the HPE structure.630 . Research and development: annual report 2007

50°2 1 0,5 0,2-0,2-0,5 -1 -250°2238.840°40°212038.638.430°30°1938.2350° 0°10°20°30°40°50°38181960 1980 2000 2020 2040 2060 2080 2100 Time series of the sea surface temperature (°C, in red) and of the seasurface salinity (psu, in blue) for the whole Mediterranean basin6ERA40 1960-20022.0721. m/s1.621. mm450.0400.0350.0300.0250.0200.0150.0100.0250.0225.0225.000600.0 24 h accumulated surfacerainfall simulated byMESO-NH (A/) and 500 hPageopotential and moistureflux from the ARPEGEClimate/OPAMED system (B/)for a simulated HPE in thefuture climate.1.2550.0Arpege-Climat Medit. 2070-2099 Heavy precipitation cases field composites, in the present climate from theERA40 reanalysis (top panel) and in the future (A2) climate from the Arpege-Climat Mediterranean SAMM model (bottom). Fields are the geopotential heightat 500 mbar (brown contours), the wind at 925 mbar stronger than 5 ms -1(blue arrows), and the moisture flux magnitude at 925 mbar (shaded areas). downscaling with Meso-NH for heavy precipitation eventsThe evolution of the frequency and intensityof heavy precipitation events is still an openquestion and cannot be simply assessedthrough a direct use of climate model outputs.To address this question, downscalingapproaches are currently designed. As forinstance, within the framework of theCYPRIM project, an hybrid downscaling (orstatistico-dynamical downscaling) methodis used to address whether frequency orintensity of Mediterranean Heavy PrecipitationEvents (HPEs) might change in afuture climate.This statistico-dynamical downscaling isbased on a two-step method: i) firstly, somecases are selected from an ensemble of environmentspropitious to HPEs for the actual climate(1960-2000) and for the future one(2070-2099) as simulated by the climate scenariosand ii) secondly, the cases are simulatedwith a fine scale non-hydrostatic modelwhich is particularly well suitable for thesimulation of processes leading to the formationof heavy precipitation events. The statisticalmethod that identifies propitiousenvironment is based on a clustering of the500 hPa geopotential field combined withcriteria on the low-level moisture flow. It hasbeen applied to the ARPEGE Climate/OPAMED outputs to identify twenty casesequally partitioned between the present andfuture climate. Then, these cases are simulatedwith the MESO-NH model at 2.5 km forthe finest domain and using as initial andboundary conditions the ARPEGE Climate/OPAMED outputs.31 . Research and development: annual report 2007For each of the 20 cases, MESO-NH producesheavy precipitating systems with 24 h accumulatedprecipitation above 100 mm andreaching in some cases more than 400 m.These results confirm that the statisticalselection is relevant to identify propitiousenvironment for heavy precipitation and thatthe dynamical downscaling is able to reproduceprecipitating systems typical ofMediterranean heavy precipitation events.Results about the evolution of heavy precipitationevents and their environment are beingfinalized, given close attention to the evolutionof key ingredients for the developmentof heavy precipitation events such as moistureflux, precipitable water, low-level jet andthe available convective instability. 7

Atmosphereand environmentstudiesIn 2007, several developments were carried out concerninghydrometeorology, oceanography, nivology, reduced visibility ormodelisation of atmospheric chemistry... Some notable progresswere made on discharge forecasts thanks to SIM improvements,on fog understanding, … Moreover, air quality ensemble forecastand desert dusts forecasts were two major innovations of the last12 months.Hydro-meteorologySea-air coupled processesduring heavy precipitating eventsFor the strongly precipitating events that frequentlyoccur over the Mediterranean basinduring the autumn, the Mediterranean Seais an important source of heat and moisture.The sea can also sometimes contribute toamplify the flood due to the sea-level riseand the generation of a strong swell, generatedby the strong winds that accompany theheavy rainfall.To study the impact on the oceanic mixedlayer of heavy precipitation and strong seawinds observed in these situations, as wellas the feedbacks on the atmosphericevents, a full 2-way ocean-atmosphere cou-pling has been designed between theatmospheric model MESO-NH, through itssurface scheme SURFEX, and an oceanic 1Dmodel (Gaspar et al.,1990). Applied to threeheavy precipitation events (Aude 12-13November 1999, Gard 8-9 September 2002and Hérault 3 December 2003) at a 2.4 kmhorizontal resolution, the coupled systemreproduces fine scale oceanic responses. Asignificant deepening and cooling of theoceanic mixed layer are thus found underthe strong winds associated with the precipitatingsystems. An impact of the precipitationis also shown through a decrease of thesalinity induced by fresh water inputs andthe building-up of inner mixed layers relativelylittle salted. Compared with a simpleone-way forcing, the 2-way interactive couplingtends to moderate the two boundarylayers responses, without modifying thehigh-resolution and short range forecast ofheavy precipitating events.This study constitutes a first step in finescaleair-sea coupled modelling and producesoutcomes for a future campaign fieldon the hydrological cycle of the Mediterranean(HyMeX). 1Improvement of the hydrological transfersin the surface model ISBAA good representation of hydrological transfersis necessary for a good simulation ofrunoff and water transfers to the rivers. Oneoption, amongst others, to improve the ISBAsurface scheme consists in introducing adiminution of the saturated hydrologicalconductivity with depth. This parametergoverns the speed of the water transfers inthe soil, its diminution being linked to thecompactation of the soil with depth.After some very encouraging applications atthe scale of the Rhône basin and at globalscale, this modification has been tested inthe application SAFRAN-ISBA-MODCOU atthe French scale. After several one-dimensionaltests, the calibration of correspondingparameters has been defined. Usingthe observed discharge observations atsome 200 stations, the parameters werecalibrated to reproduce as faithfully as possiblethe observed discharge.The validation showed that the improvementwas significant over most stations(increase of the Nash criterion). The impacton the root reservoir wetness is almost neutral,while the humidity of the sub-root reservoiris increased, allowing a betterrepresentation of floods and low flows. Thisnew calibration improves the overall qualityof the SAFRAN-ISBA-MODCOU runs. It will beused either in the framework of dischargeforecast or on impact studies of climatechange. 232 . Research and development: annual report 2007

FsolAtmosphèreSolFirSurfex (schèma de surface)ConvectionPMélangeverticalSSTColonnesd'eaude merVentτu, τvHModèle Méso-NH(Lafore et al, 1998)LE = ζ x EModèle océanique 1D(Gaspar et al, 1990)Océan The principles of the MESO-NH(SURFEX) / 1D oceanic model coupling:the variables exchanged at the air-seainterface are the radiation fluxes (Fsoland Fir), the turbulent fluxes (τ, H, LE)and the precipitation rate (P).Bathymètrie1108Obs.AvantAprèsLa Garonne à Lamagistère(2002-2003)mm/d6Improvement of the dischargeof the Garonne at Lamagistère(Haute-Garonne) duringthe winter 2002/2003.4202Novembre Janvier MarsDate33 . Research and development: annual report 2007

Extension of the reanalysisof the hydrometeorological system SIMThe hydrometeorological system SIM(Safran-Isba-Modcou), used operationally atMétéo-France since 2004, permits a continuousand real-time monitoring of soil waterresources over France.In order to detect anomalies concerningwater resources availability and to allow abetter qualification of a specific hydrologicalseason, the reanalysis of the model is dailyused as reference. In 2007, the reanalysis ofthe SIM model has been extended over thewhole 1970-2006 period using ERA40(1957-2001) atmospheric reanalysis ofECMWF and observations from the Météo-France climatologic network.The extension of the temporal period coveredby the reanalysis will be continued in2008. This work will permit to obtain a climatologyof the model covering the years1958-2008 with an innovative dataset of 50years of soil water resources at a 8 km spatialresolution all over France.This reanalysis will be important for futurestudies, especially for assessing the impactof climatic changes on the hydrologicalresources. 3Ensemble stream-flow predictionsusing the SAFRAN-ISBA-MODCOU chainThe hydrometeorological suite SAFRAN-ISBA-MODCOU (SIM) simulates the distributedsurface hydrologic budget and theassociated streamflows for the whole metropolitanFrance. SAFRAN is a meteorologicalanalysis system, ISBA is a land surfacemodel, MODCOU a hydrological model(developed by the Ecole nationale supérieuredes Mines of Paris) which simulatesthe flows over 800 French rivers places.The availability of this chain allowed newresearch on daily streamflow prediction, basedon the ensemble prediction system of ECMWF.For that, precipitation forecasts are disaggregatedat the scale of France (to take into accountorography and forecast biases). The ISBA-MODCOU model runs for each member of theensemble forecast. The performances of theensemble streamflow forecast were testedover a period of more than one year.Performances are satisfactory, despite a lackof spread at short time scale, especially forprecipitation. The ensemble streamflowforecast will allow to improve the forecastterm and the pre alert for the operationalservices. A test using the short term ensembleforecast from the ARPEGE model showedan improvement for short term forecasts,especially for small basins.In the future, tests of the system will becontinued. The emphasis will be put on theimprovement of the model initial state,using an assimilation of the observed discharge.4Soil moisturemonitoring: modellingversus satellite and insitu observationsSurface soil moisture can be estimated byusing microwave remote sensing data. Thisquantity is simulated by land surfacemodels. Automatic probes allow the continuousmonitoring of soil moisture profiles,in situ. To compare soil moisture estimatesgiven by various techniques improves theunderstanding and the modelling of biophysicalprocesses.The satellite mission SMOS (L band radiometer)will provide surface soil moistureestimates from space with a sampling timeof 2-3 days and a spatial resolution of 20 to60 km. A number of existing soil moistureproducts derived from satellite observationshave the potential to be used in synergywith SMOS. The C band wind scatterometerdata (ERS-Scat, ASCAT onboard METOP) orthe C and X band passive microwave data(AMSR-E onboard Aqua), already providesurface soil moisture estimates, at a similarspatial resolution. ASCAT onboard METOP(an operational instrument) will enableEUMETSAT to issue global soil moisture productsat a similar sampling frequency asSMOS. In situ soil moisture observations areavailable for south-western France : SMOS-MANIA (2007-2013) is a network of 12RADOME weather stations equiped to measuresoil moisture and temperature profiles(-5, -10, -20, -30 cm).The comparison of in situ data with simulations(SIM) and the available remote sensingproducts (see figure) permits to crossvalidatethe satellite products with themodel and to verify the representativenessof in situ data. 534 . Research and development: annual report 2007

31.2Indice d'humidité du sol1. moyen FranceMoyenneQuintiles 20 et 80 %Mini - max (1970-2005)2003J F M A M J J2003A S O N DMean soil water index (SWI)over France for the year 2003and comparison with statisticson the 1970-2005 periodSIM vs. AMSR (VUA)4° W 2° W 0° 2° E 4° E 6° E 8° E550° N4m 3 /s2 0001 5001 000Daily streamflow at "la Seine à Paris (pont d'Austerlitz)"Débit opérationnelObservationsQ90 climMédiane climQ10 clim48° N46° N44° N500SIM vs. ERS4° W 2° W 0° 2° E 4° E 6° E 8° E05 12 19 26 2 9March 2001April Ensemble streamflow predictionfor the 2001 flood in Paris.Observations: black,simulation with SAFRAN analysis: red,ensemble prediction: dashed lines,green: climatological thresholds50° N48° N46° N44° NCorrelation maps between the surface soilmoisture simulated by SIM over Franceand 3 satellite products, for the 2003-2005period.From top to bottom: AMSR-E (AmsterdamUniversity), ERS-Scat (Vienna University),AMSR-E (NASA, version 3-B03).SIM vs. AMSR (NSIDC)4° W 2° W 0° 2° E 4° E 6° E 8° E50° N48° N46° N44° N-1 -0.3 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 135 . Research and development: annual report 2007

Oceanography(modelling and instrumentation)Sea surface salinitymeasurementThe Centre de Meteorologie Marine (CMM)will take part in the validation and calibrationof ESA SMOS satellite (Soil Moisture OceanSalinity) which will be launched in 2009.The GLOSCAL (Global Ocean SalinityCalibration and Validation) project aims tostudy the Sea Surface Salinity data (SMOSdata, AQUARIUS data, in situ data) in collaborationwith the national and internationalscientific community. The Sea Surface Salinityis important for a better understanding of theclimate.For this purpose, drifting buoys fitted withconductivity sensors were deployed off theAmazon river in the framework of PLUMANDand AMANDES campaigns, and in Biscay Bayfor CAROLS experiment. The deployment ofbuoys off the Amazon river had two aims: ascientific one (to analyse the salinity variabilityin surface de-salted waters) and an instrumentalone (validation in tropical oceans).The aim is to have about thirty buoys to beready to be deployed when SMOS will belaunched. 6E-Surfmar:European surface marineobservation programmeSince 2003, the surface marine meteorologicalobservation has been organized in Europein the framework of Eucos, a compositeobservation programme of Eumetnet. Météo-France ensures the leadership ofE-Surfmar, a programme which gathers observationsfrom VOS (Volunteer ObservingShips) recruited by EMS as well as from driftingand moored buoys. The programme issteered by two advisory groups: one for shipsand one for buoys. In 2007, its budget wasabout 820 k€.Whereas the number of observations carriedout by conventional ships are ever and everdecreasing, those collected by automatedstations installed aboard European shipshave doubled over the past 5 years. On average,observations have increased from 300to 700 a day in the North Atlantic and in theMediterranean Sea.By the end of 2007, about 100 drifting buoys,funded by the programme, reported morethan 2200 observations of air pressure andsea surface temperature per day, a levelnever reached before.E-Surfmar is mainly concerned with the automationof the observation, the decrease ofproduction cost, the improvement of its qualityand the reduction of transmission delays.In 2007 the Iridium satellite system showedits potentialities compared to Argos in reportingdrifting buoys data ashore. The decisionto progressively extend this communicationsystem to all the drifting buoys was thereforetaken. 7Participationin the InternationalPolar Year (IPY)Meteo France contributes to the InternationalPolar Year (IPY 2007-2009) through theE-SURFMAR programme.E-SURFMAR funded some buoys which weredeployed in the framework of the InternationalArctic Buoy Program (IABP), a regionalaction group of the DBCP (Data BuoyCooperation Panel). Two buoys were airdeployed during the Summer 2006. Sevencheaper ones were put on the sea ice duringthe Summer 2007 by the German researchvessel POLARSTERN. By December 2007,eight out the nine buoys were correctly working,transmitting their hourly data througheither the Argos system satellite or theIridium one.The main objective is to take advantage ofthis campaign to contribute to the densificationof the air pressure measurement networkin this area and to quantify its impactthrough further studies.In September 2006, the sailing-ship TARA V(ex-ANTARCTICA) which began a two-yeardrift in the sea ice of the Arctic Ocean sinceSeptember 2006, was also equipped with anautomatic weather station. 9Use of Iridium for transmission of surface marine dataThe tests realized in 2007 to use Iridiumsatellite system to transmit drifting buoysdata were successful. The system is reliable,quick and cheap. By the end of 2007, about20 SVP-B drifting buoys fitted with a SBD(Short Burst Data) transmitter were in operationin various ocean: Arctic Ocean, NorthAtlantic Ocean, Black Sea, South AtlanticOcean, and Indian Ocean. Every hour, thedata are received at CNRM/CMM in Brest,coded in FM18-BUOY messages and sentonto the GTS within less than 10 minutes.Forty-five Iridium buoys, funded by the E-SURFMAR programme, have been purchased.Next year, they will be deployed at seatogether with Argos buoys. Future orders forthe E-SURFMAR network should be Iridiumbuoys only.In 2007, CMM also developed a minimalship borne Automatic Weather Station (AWS)to meet E-SURFMAR requirements i.e. measuringthe atmospheric pressure at least.This AWS, so called Baros, is fitted with abarometer, a GPS and a SBD Iridium beacon.This prototype was put on board the Frenchtrawler Jericho. It has been working perfectlysince the beginning of November 2007. Datahave been sent in real time onto the GTS inFM13-SHIP messages. Four more stationsdevoted to E-ASAP ships not yet equippedwith an AWS, are being produced. 836 . Research and development: annual report 2007

6 Salinity buoys: drifting buoysfitted with conductivity sensors7Drifting buoys (measuringatmospheric pressure)trajectories in the Eucosarea in November 2007 Buoy on the sea iceBuoys trajectories in November2007 (in red E-SURFMAR buoys)9 Iridium buoy at sea.8 DBCP Iridium Pilot Project Map(Status 19 December 2007)37 . Research and development: annual report 2007

The moored buoys10The open ocean buoys Brittany (moored by2 100 meters depth) and Gascogne (mooredby 4 500 metres depth) are maintained incooperation with the United Kingdom MetOffice.In addition, Météo-France is operating openocean moored buoys in four other places: twooff the French West Indies by 5 500 metresdepth and two others in the MediterraneanSea by 2 300 metres depth. The buoys weigh3.7 tonnes, and measure 2.8 metres in diameterand 6 metres overall height. The hourlyobservations are transmitted in real time viathe METEOSAT satellites. 10From MERSEA to My Ocean : towards an integratedEuropean system for operational oceanographyThe aim of the European MERSEA Project(2004-2008), funded by the EuropeanCommission and coordinated by IFREMER, isto develop and to demonstrate, in pre-operationalconditions, an integrated Europeansystem for operational oceanography, in responseto the GMES requirements. This systemis composed of analysis and forecastcentres for the global ocean (under MercatorOcean’s responsibility) and for regional seas(Mediterranean Sea, North-Eastern Atlantic,North and Baltic Seas, Arctic Ocean), as wellas satellite and in-situ data centres providingthe necessary observations.Météo-France contributes to MERSEA throughresearch activities performed at CNRM aboutatmospheric forcing fields and the impact ofhigh resolution global ocean analyses on seasonalprediction, demonstration activities performedin the Marine Forecast andIn classical atmospheric circulation models,the estimation of air-sea turbulent fluxes(wind stress, sensible and latent heatfluxes) relies on the use of « bulk » formulationstogether with air-sea parameters andexchange coefficients for wind, temperatureand humidity.In 2007, a new parameterisation of the neutralexchange coefficients named ECUME(Exchange Coefficients from Unified MulticampaignsEstimates) was set up using theALBATROS dataset (http://dataserv.cetp.ipsl.fr/FLUX/) which gathers all the measurementscollected during several cruisesover the past ten years, in close collaborationbetween CNRM and IPSL. This parameterisationis particularly consistent as itprovides an analytical formulation for all theexchange coefficients (for wind, tempera-Oceanography Division about the use of surfacecurrent forecasts for sea state and oil driftprediction, and development and productionactivities performed at CMS about sea surfacetemperature satellite observations.In 2007, the CNRM has demonstrated anddocumented the positive impact of newlydeveloped turbulent fluxes parameterisationson the global ocean circulation simulation.At CMS, the processing of new satellitemulti-sensor sea surface temperature products,covering the Atlantic Ocean, has beenimplemented, and they are now made availableto MERSEA users.In 2008, the transition from MERSEA to MyOcean (2008-2011) will take place. This newproject, funded by the European Commission,will transfer into operational exploitationthe system developed in the frameworkof MERSEA. 11ECUME: a new parameterisationfor air-sea turbulent fluxesture and humidity) derived from turbulentfluxes estimates using simultaneous measurementstogether with homogeneousmethods, while covering the widest range ofwind and of atmospheric stratificationconditions.A first evaluation of this parameterisationwas carried out in the MERSEA IntegratedProject framework using the global oceanmodel OPA, developed at LOCEAN. Thisparameterisation is now being evaluated inatmospheric models ranging from theARPEGE-Climat model to the meso-scaleAROME and Meso-NH models. Two recentstudies have indeed demonstrated thebenefit of using this parameterisation in theMeso-NH model for the simulation of boththe intense Mediterranean rainfall eventsand of hurricanes. 12Replacementof a buoy inMediterraneanSea in February2007.Laboratory experimentson Internal tideInternal gravity waves in oceans, as well asin the atmosphere, interact with large-scaleprocesses. In the ocean, the counterpart ofthe drag force for mountain waves is theamount of energy extracted from the barotropictide due to the formation of the internaltide. This conversion rate is an essentialinformation if the role of the internal tide inmixing the abyssal water masses is to beunderstood.Rough estimates of this conversion rate areavailable, based on satellite data (Munk andWunsch, 1998). These data also reveal thatthe energy conversion mostly occurs at topographicfeatures, but many questions relativeto internal tides generation,propagation and dissipation remain to besolved.In this context, laboratory experiments onthe generation of internal tidal over a seamountare performed. The tidal problem ismapped to an oscillating ridge in a staticfluid. The Schlieren synthetic technique andthe Particle Image Velocimetry techniqueprovide measurements of the density andvelocity fields induced by the waves.The toolbox integrated into the numericalmodel Symphonie developed by theLaboratoire d'Aérologie in order to analyseinternal tides energetic transfers must nowbe validated. These studies will improve ourunderstanding of the thermohaline circulation,which works on a temporal scale of athousand years. Therefore, they also contributeto climate research.1338 . Research and development: annual report 2007

12 Multi-sensor sea surface temperature field obtained on 1 st December 2007,combining infra-red and microwave observations from geostationary and polarorbiting satellites.111314 Neutral exchange coefficients for the wind (Cdn), temperature (Chn),and humidity (Cen) issued from the ECUME parameterisation (red line),as a function of the wind gradient between the sea surface and 10 mheight. Each dot represents a value provided by the ALBATROS dataset.Several (among the most commonly used) bulk parameterisations arealso drawn. Density fieldinduced byinternal tidebeams72 hours drift observed with a buoy (black) and simulated by Mothy with only the wind forcing (brown) or when the currentsof a monthly climatology are added (green), or the MFS analysis (red), or the Mercator-Ocean PSY2V2 analysis (blue).On the left : drift started on the 13 th October 2007 and we note a good agreement with the Mothy drift using the climatology whereasthe oceanic systems reproduce badly the liguro-provencal current.On the right : the drift start on the 16 th November 2007 near the Balearics Isles and the Mercator currents are here the most accurate.Observed and forecasted oil spill driftinter-comparison in the Mediterranean SeaIn the framework of its national and internationalduties, Météo-France operates theMothy drift model. It is composed of a 2Docean model (computation of currents due towind and tides) and of a model simulatingthe behaviour in the ocean of oil spills (orobject).However, in some cases, the low frequencyoceanic circulation can become the main instigatorof the drift. One Météo-France of theparticipations to the European project MER-SEA (Marine Environment and Security for theEuropean Area) consisted precisely in theassessment of this contribution.Thus, an experiment in the MediterraneanSea has been organized during the autumn2007 with French (Cedre, Ifremer), Norwegian(Met.No) and Cypriot (UCY) services in orderto deploy buoys emulating a surface oil spill :3 near Cyprus and 8 off Toulon in the SouthEast of France. The experiment lasted formore than 3 weeks and allowed to collectprecious data on oil spill drift in a sea wherethe drift forecast systems have not often been39 . Research and development: annual report 2007validated while its dynamic is very complex(variable currents associated with smalltides). The Norwegian (OD3D), the Cypriot(MedSlik) and the French (Mothy) drift systemswill be inter-compared and the differentoceanic operational systems will be tested(Mercator (France), MFS (Italy) and CYCOFOS(Cyprus)).Studies with these data started in Novemberand will continue once the Mersea project isover, to improve the existing systems.14

15 Instrumentation for humidity and temperature measurementsinstalled on Toulouse Météopole during the Toulouse-Fog campaign.This device allowed measurements at 0.5, 1, 2, 5 et 10 m height.Atmospheric environmentField experiments dedicated to fog:from Paris-Fog to Toulouse-FogRisk maps of mistand fog: “CARIBOU”The short-term forecasting of fog is a difficultissue which has a large societal impact. Forexample, adverse visibility conditions are aproblem for the security of air transportationor traffic.CNRM-GAME has made significant efforts toimprove the knowledge of the mechanismsinvolved in the life cycle of fog. Research isgoing on to improve fog forecasting bynumerical models, and particularly, whatinfluence have both surface heterogeneitiesand aerosol on fog.The PArisFOG experiment has been performedduring the 2006-2007 winter season toobserve simultaneously all these processes.The project is based on an experimentalsetup that gathers instruments from differentresearch laboratories (IPSL, CEREA andCNRM). Instruments have been deployed atSIRTA from November 2006 to April 2007.Data from the PArisFOG field experimenthave been validated and are available onthe web server http://parisfog.sirta.fr/ .Unfortunately, technical problems made itimpossible to collect enough observationsof microphysical parameters during Paris-Fog. However, it is necessary to improve ourknowledge on the microphysical propertiesof fog, in order to define, for example, newintegrated system for road traffic. A newfield experiment, called Toulouse-Fog, hasbeen decided for the 2007-2008 winter season.Toulouse-Fog mainly focussed onmicrophysical parameters on fog layers.These data will allow to investigate thedynamical, microphysical and radiativeevents which contribute to the formationand dissipation of fog. Improved physicalparameterizations validated against datafrom Paris-Fog and Toulouse-Fog will also bedefined and included in future numericalweather prediction models. 15Fog ensemble prediction systemOver main international airports, air traffic isvery dense. Consequently, low visibilityconditions, occurring with fog and lowclouds, strongly influence the airport managementand safety. The economic issuesrelated to the reduction of visibility overthese airports are huge for the civilian andcommercial aviation trades.A Local Ensemble Prediction System (LEPS)has been designed for the prediction of lowvisibility events at Paris-Roissy Charles deGaulle airport to optimise airport managementand flight scheduling. The ensembleprediction system has been built around thenumerical prediction model COBEL-ISBA. Thislocal single column model, developed for theprediction of fog, is operational at Roissy airportsince 2005. LEPS is an original systemwhich provides confidence indexes for localfog forecasts. These probabilistic forecastsplace the user at the centre of the decisionmaking process. As a consequence, userscan use the LEPS forecasts to minimise hisoperating losses related to fog occurrences.In conclusion, LEPS is a reliable predictionsystem for forecasting low visibility events atCharles de Gaulle airport. Moreover, the systemis portable and can be installed at anyother airports. The system is an efficienttool and a valuable help for both managementand safety for the civil aviation in theaeronautic area. 16Since the end of June 2007, risk maps ofmist and fog are produced in an operationalway at Météo-France. These maps show anestimation of the risk of occurrence of thesephenomena, elaborated by merging satelliteobservations (MSG cloud type images, bySAF-NWC), surface analyses (DIAGPACK analyses)and radar data (radar quantitativeprecipitation estimation PANTHERE).The cloud type images, produced by CMSfrom the geostationary satellite MSG data,supply a spatialized information about thepresence of low clouds, in case of no cloudylayers at higher levels, obviously.The DIAGPACK surface analyses, elaboratedevery hour by optimal interpolation usingALADIN fields as guess and all availableground observations, aim at fitting at bestthe latter ones and so supply fields closer tothe observations.The 2 m relative humidity and 10 m windfields stemmed from these analyses, inassociation with the PANTHERE radar quantitativeprecipitation estimation, allow to discriminate,within the cloud type image,between “low clouds” being in contact ornot with the ground. So, the risk of occurrenceof mist and fog, that is visibility globallylower than 5000 m, is estimated allover the French metropolitan territory, with a3 km spatial resolution and a one-hour timestep.Currently, the main limit of the product is alack of quantification of the fall in visibilityencountered within risk areas. A study is inprogress in order to associate a class of visibilitywith the notion of risk. 1740 . Research and development: annual report 2007

17Forecast exampleForecast hoursObservations on the airpor tConfidence indexProbability6h 8h 10h 12h 14h 16h 18hCertainP>90%FogLikely50=

Atmospheric chemistry and air qualityTaking into account uncertaintiesin mesoscale dispersion modellingPonctual source atmospheric dispersionmodelling is based on three main components:the meteorological parameters (wind,vertical stability…), the representation of theemission source, and the numerical representationand parameterization of transportand of the possible physical, chemical orradiological processes involved. Each ofthese components has its own uncertainties,and it is an objective to better take them intoaccount when estimating the impact of anaccidental pollution release.Simulations were performed with the Perlesystem, used at Météo-France in operationsfor modelling the dispersion of pollutants atshort distance, in order to illustrate the uncertaintiesconnected with the meteorologicalforcings and with the representation of theemission source. In the first case, the ensembleweather prediction based on the Arpègemodel has been used as input to Perle; thisDesert dusts are atmospheric particles withsizes ranging between 1 and 10 micrometers,produced by wind erosion in arid andsemi-arid areas. As everyone has alreadyexperienced, this aerosol can be transportedover thousands of kilometres, beforebeing deposited again. In addition to stronghealth and air quality impacts, desert dustsaffect several sectors: operations of thearmed forces, visibility, as well as, for instance,satellite imagery…Forecasts of dust concentrations and depositionfluxes are thus much needed in orderto anticipate major events and take welladaptedprecautions. Research activities atMeteo-France in collaboration with LISAhave allowed to set up an operational dustforecast service. Since November 2007,daily dust forecasts are provided for up tofour days in advance. The 3D chemistry andOperational forecastsof desert dustsprediction ensemble provides 11 meteorologicalscenarios obtained from slightly differentinitial conditions. The variability of thesimulations of dispersion reveals a very highsensitivity of the results to weather conditionsin certain types of weather. It was alsoshown that perturbations to the specificationof the source term led to very different evolutionsof the pollutant plume, and therefore tomarkedly different potential consequences.This is a concern, as these characteristics aregenerally not precisely known in the event ofa real accident.A prototype has been implemented on PCcluster and on the super-computer of Meteo-France. It already allows to appreciate, inpost-accidental mode, the variability of dispersionscenarios provided by Perle usingensemble weather prediction or whenmaking alternative assumptions on the characteristicsof release source. 19transport model Mocage is used for thisapplication and it takes into account dustsemissions from the two major worldwidesources: the Sahara desert and Saudi Arabiaon the one hand, China on the other hand.Dusts are transported and deposited bywinds and rain forecasted by Météo-Franceoperational meteorological suites, Arpegeand Aladin.After a detailed validation activity and severalmonths of testing in near-real time, theoperational dust configuration of Mocageallows to provide a reliable and robust forecastservice to users. In particular, all theFrench air quality regional networks getMétéo-France dusts forecasts needed tointerpret observed peaks of PM10, fromthe national air quality platform Prév'Air(http://www.prevair.org/) of the French Ministryof Environment. 20Towards the useof "backtracking" toolsfor operational crisismanagementDuring a crisis management, in particular ofthe nuclear kind , it is of prime interest to beable to determine the origin in space and intime of an atmospheric pollution, which hasbeen detected at one or several locations ofa measurements network. If the question"where is the air mass coming from?" can beanswered rapidly with lagrangian trajectories,it is only in recent years that moresophisticated "backtracking" tools haveemerged. These tools correspond to theintegration backwards in time of 3D dispersionmodels, providing “retro-plumes”. Themethods used share theoretical conceptswith meteorological data assimilation;“backtracking” can be used for instance todetermine the 3D "field of view" of a givensite, at any given time in the past. TheCTBTO, in charge of monitoring the treatybanning nuclear tests, has recently askedWMO to add to its missions the operationalsupport in “backtracking”.Météo-France’s CNP is one of WMO’s eightRSMCs worldwide. In 2007, CNP has beeninvolved in an exercise in support to CTBTO.During one week, retro-plumes were calculatedon alert and provided in near-real-timeto the CTBTO in Vienna. The CTBTO was responsiblefor cross-checking the results fromthe different RSMCs, and for determining thelikely characteristics of the fictitious source(s).Within Météo-France, calculationswere made with the "reverse" configurationof the chemistry-transport model Mocage.The figure presents an example of validationof retro-plumes computed with Mocage bycomparison with reference data from theCTBTO.Such exercises of "backtracking" will be carriedout regularly and, in the event of a realcrisis, RSMCs could be asked for support forboth plumes (direct) and retro-plumes(inverse) results. The "direct" and "inverse"configurations of Mocage will be available inpermanent operational mode at the CNP in2008. 2142 . Research and development: annual report 2007

19 Dispersion as a function of varying release heights.For the case of the fire of the Buncefield oil depot (England,December 2005), the dispersion on the horizontal (left)and on the vertical (right) is shown 5 hours after the startof the release in 5 colours corresponding to 5 different initial heights :between 0 and 100 (red), between 100 and 250 m (pink),between 250 and 500 m (green), between 500 and 1000 (blue)and between 1000 and 2000 m (dark blue).20 An exceptional event of trans-AtlanticSaharan dust transport onto Martinique(M on the map) in mid-May 2007. Intersection (blue) and union (violetand blue) between retro-plumes computedby Mocage and by the CTBTO, for a situationin June 2007 at two sites located in Antarcticaand Argentina.2143 . Research and development: annual report 2007

22ab50 hPa wind analyses (reference)Impact of ozone assimilationon wind velocity at 50 hPa (%)c10 m/s 10 m/s10080604020105-5-10-20-40-60-80-10050 hPa wind analyses (ozone assimilation) 50hPa horizontal wind (in m.s -1 ) in averagefor the period January 23 to January 31, 2006.Experience without assimilation of ozone (a), experiencewith assimilation ozone (b) and percentage differencebetween the two experiments (c).Dynamical impactof ozone assimilation in ARPEGEEnsemble Air QualityForecast for EuropeThe assimilation of satellite measurements ofchemical constituents allows to build reliablespatial and temporal distributions for keyatmospheric gases, such as ozone. It is nowexpected to retrieve some information onatmospheric dynamics from the deformationof the structures of ozone in the lower stratospherewhere its lifetime is sufficiently long.This information, additional to the one containedin operational meteorological observations,can potentially improve numericalweather forecasting, particularly in high altitude,in areas with poor meteorological coverageor for medium-range forecasts.In order to characterize this impact, we haveused two tools: the first one is a dedicatedchemical assimilation suite, which is basedon the chemistry-transport model Mocage ofMétéo-France and on the Palm software ofCERFACS; the other one is an extension of theoperational NWP suite ARPEGE, which assimi-late simultaneously meteorological andozone data. Specifically, the 4Dvar algorithmof ARPEGE was used to assimilate stratosphericozone observations from the AURA/MLSsounder together with meteorological observationsconsidered in current operations atMétéo-France. In our experimental context,the variable "ozone" is treated as a passivetracer in ARPEGE while its first-guess, an independent3D field analysis of ozone, is providedfor each assimilation cycle by Mocage-Palm.For the first time to our knowledge, the assimilationof actual ozone satellite measurementsin the NWP suite ARPEGE has showna non-neutral dynamical impact, althoughrelatively small at this stage. The mainimpact is a slight improvement in the predictionof wind beyond 24 hours at 50 hPa(~ 20 km) in the tropical region. Further studiesare on-going. 22Simulating the impact from transport meanson atmospheric chemistry and climateWithin the European research programQUANTIFY whose aim is to study the effectsof terrestrial, sea and aircraft transport onthe atmosphere and the climate, theARPEGE-Climat model of CNRM has beenadapted to take into account these features.A main difficulty is to link small-scale phenomena(e.g. contrails from aircraft for instance)to the global scale represented byARPEGE-Climat. To bridge this gap, a “fuel”tracer is added to the model, with a lifespanvarying from 50 minutes (typical for boats)to 2 hours, around 10 km of altitude (whichcorresponds to the dispersion of contrailsgenerated by airplanes). Thus, ARPEGE-Climat considers the radiative effect oftransport by altering cloudiness. The chemi-cal impact is also taken into account bymodifications of the simplified chemistry ofthe ozone layer that now can consider theeffect of main pollutants that are nitrogenoxides, carbon monoxide and water vapour.Using this version of ARPEGE-Climat, simulationsfor the XX th and the XXI st centuries willbe made during 2008 to assess the impactof transport for next decades.In addition, ozone distributions simulatedby ARPEGE-Climat will be compared to theMOCAGE model which has s a more sophisticatedchemistry. This will be done for a 10year snapshots, representative of today’satmosphere and for the years 2025, 2050and 2100. 232007 was marked by the first demonstrationof ensemble air quality forecasts overEurope, a decisive step towards providing anoperational pan-European core service.These activities take place within the projectsGEMS and PROMOTE (ESA), upon whichthe operational GMES Atmospheric Servicewill be built. Météo-France has a coordinatingrole together with its partners at Prév'Airat the European scale, and provides forecastswith the chemistry-transport modelMocage.Validated systems for assimilating and forecastingair quality over Europe with relativelyfine resolutions (less than 50 km) have nowemerged, particularly in France with the platformPrév'Air. It is interesting to take advantageof the dispersion between models todevelop better forecasts and to estimatetheir probabilities of occurrence. Since July2007 and in the context of PROMOTE, threeoperational models (CHIMERE, EURAD andMocage) are combined to offer the firstdemonstration of an ensemble Air Qualityservice to potential users. Within GEMS, animportant harmonization work has beenachieved on emissions, meteorological forcingsand chemical boundary conditions;with about ten models involved, activitiesfocus on the exploitation of uncertainties inthe chemistry-transport model themselves,as well as on different possible methodologiesfor ensemble forecasting.At the same time, an unprecedented effort ofconcentration in near-real-time of Air Qualityobservations in about fifteen European countrieshas been done, in collaboration withthe local, regional and national measurementnetworks. These (non-validated) dataare converted into the BUFR format and areused for forecasts’ verification and surfacechemical data assimilation. 2444 . Research and development: annual report 2007

Mocage T21L60Fuel3 “Fuel” tracer distribution at level 250 hPa (correspondingto cruise altitude for subsonic aircraft). Apart from main airports,main atmospheric corridors can be seen, as the Northern Atlanticone, linking Europe to America.Traceur fuel (ppbv)24Décembre 2001 A Simulated Observing System Experiment (OSSE)conducted with Mocage-Palm for CO over Europe.The assimilation of pseudo-observations built froma reference model run (top) can effectively constraina simulation that starts with an erroneous initial state(low). In the case studied, it takes about 24 hoursto correct the initial error.23257,36 hPaOn the website of ECMWF, forecasts fromMocage are presented together with severalother individual forecasts from otherstate-of-the-art models. All contributeto the demonstration of a European air qualityensemble forecast service.257 aout 2007 - 0 h 7 aout 2007 - 3 h 7 aout 2007 - 6 h 8 aout 2007 - 0 hRéférenceGeo OSSECOppbv300280260240220200180160140120100806040200Preliminary studies for air quality observationfrom the geostationary orbitThe observation of air quality from space is achallenge, especially in the context of GMES.In addition to ground-based observations,satellite measurements would provide a complementaryspatio-temporal coverage, as wellas some vertical information in the loweratmosphere. The French operational consortiumPrév'Air for Air Quality favours a geostationarysounderwhich can provide the neededtemporal resolutions, given the fast diurnalvariations of target pollutants: ozone, NO 2 , COand aerosol optical depth.The development of a remote-sensing instrumentthat would be suitable for a geostatio-nary platform, and would allow sufficient precisionand sensitivity raises many questions.In collaboration with LA, LISA and EADS/Astrium, CNRM contributes by conductingOSSEs (Simulated Observing SystemExperiment). The Mocage chemistry-transportmodel is used to simulate pseudo-observationsthat follow the potential characteristics(geometry, frequency, errors,…) of a geostationaryinstrument; then, we assimilate these"synthetic" observations in order to quantifytheir ability to constrain forecasts of air quality.Thus, OSSEs provide an objective basis todevelop and optimize the instrument.We illustrate here results from an OSSE for COobservation over Europe. From a referencesimulation performed with Mocage, geostationaryCO pseudo-observations are built.Starting from an erroneous initial state, weassimilate these in the model. Within 24 h,the CO assimilation run is progressively catchingup with the reference which is an indicationof the ability of the observing system toconstrain the simulation and to compensateerrors (here on the initial condition). This workis also performed in the context of many internationalcollaborations. 2545 . Research and development: annual report 2007

Avalanches and snow cover studiesA new wind blows on the Nivôse networkSince the first station installed in 1981, thenetwork of high mountain automatic Nivôsestations has been becoming one of the maintools for the operational avalanche forecasting.The French Snow Studies Centre (CEN) isresponsible for the current deployment of thethird generation of stations, which aims toimprove quality and reliability of measurements.This new station keeps a maximal mechaniccompatibility with existing infrastructures, inorder to reduce replacement costs. For thesame reasons, the alimentation by batteriesand solar panels and the satellite transmission(using the Météosat system) have beenkept.The station is now equipped with the newCampbell datalogger CR1000. All the sensorshave been changed, using, for instance, anew Young anemometer (wind speed anddirection) not too much perturbed by icing,the new Campbell snowdepth sensor SR50A,an optimised ventilated air temperature sensor,…Particular attention has been paid toreduce the station consumption, which was amajor source of malfunctioning of the previousstation generation.Early 2006, 21 stations were initiallydeployed in the Alps, the Pyrenees and theCorsica massifs. During the summer 2007, 15of them were replaced. Moreover, two newstations have been installed in southern Alps(Orcières in the Champsaur massif andMillefonts in the Mercantour massif), hencereaching a total number of 23 stations.Next summer this rejuvenating operation ofthe whole network will be continued andcompleted, in order to monitor high mountainconditions for years to come. 26The DOLMEN project : a successfully transferfrom research to operational environmentBegun in February 2004, the DOLMEN projectaimed at improving the development of asecond version of the operational applicationsused by avalanche forecasters in eachdepartmental centre (CDM). The DOLMEN projectwhose aim was to improve the developmentof a second version of the operationalapplications used by avalanche forecasters ineach CDM started in February 2004.Its three major objectives were :• The implementation of the SAFRAN chain(meteorological analysis) / the Crocus chain(snow model) / the Mepra chain (avalanchehazard assessment) in a 100 % operationalenvironment (Toulouse computing centre anddepartmental servers). These chains, developedby CEN, have been operated in a semioperationalmode for several years but only asmall part of the results was available for endusers.• The increasing of functionalities of the softwarenamed “Poste Nivologie" with anaccess to all the modelling results. Severalcomparison products between observationand model were developed especially todetermine the relevance of modelling.• The adaptation to the new codification systemof snow-meteo data.The deployment in December 2007 of the versionV2.3 which fulfilled all these objectives,marked the end of the project. This transfer,which reflects a strong integration of thesnow monitoring system in the technicalarchitecture of Météo-France, has also beenfollowed up by many training courses eitherfor users of these new tools in CDM or forcomputing regional units in charge of monitoringthese applications..Subsequent developments will be performedwithin METEO-FRANCE standard framework.CEN obviously stays in charge ofscientific models improvement, as well asthe technical and functional responsibility ofthe tool DOLMEN. 273D modellingof water vapor diffusionin snow frommicrotomographicimages: applicationto isothermaletamorphismSnow, when placed in isothermal conditionsand at negative temperatures, turns into abrittle material made of small roundedbodies which are typical of microstructurescommonly obtained during the sintering ofceramics. This complete transformation isclassically considered as limited by the watervapour diffusion that occurs in the porespace of the snow structure. In order to validatethis hypothesis, the water vapour fieldfrom small snow samples was modelizedfrom tri-dimensional images obtained by X-ray microtomography.Thanks to already developed algorithms, thecurvature field is first estimated at the air-iceinterface. By using the Kelvin’s equation, onecan define the vapour pressure conditionsnear the interface. Then, the diffusion equationis numerically solved with an iterativemethod, which provides, after convergence,the water vapour field in the pore space (seeFigure). The local vapour gradient, which isestimated close to the interface, yields thegrowth rate at each point of the interface (seefigure).From these results, the water vapour diffusioncan be seen as a limiting mechanism for isothermaltransformation. However they do notinvalidate other mechanisms that could happeninside the snow, such as surface reactionphenomena or growth at grain boundaries.This model, which can be used to simulate theevolution of small snow structures, is a firststep for future more precise comparisons betweendifferent mechanisms.2846 . Research and development: annual report 2007

the new Nivôse station of la Meije,at 3 100 m a. s. l. in the Oisans massif.26“Poste Nivologie” software .Visualization of modelling results.Map of precipitations over FrenchAlps massifs.Chablais : Simulated snow depthrepartition and snow profiles.27a28 ba - 2-D slice of the vapour pressuremap computed from a snow imageof a sample that has beenmetamorphosing during 12 days underisothermal conditions. Image edges areabout 3 mm wide (300 voxels).b - Map of the local growth ratescomputed from an image of naturalsnow assuming a vapor diffusion-limitedmechanism in the snow matrix.Image edges are about 3 mm wide(300 voxels). Growth rates rangefrom –0.15 x 10 -10 m/s (green)to +0.15 x 10 -10 m/s (red).47 . Research and development: annual report 2007

Instrumentationfor ResearchThe instrumental teams were mainly concerned in 2007 by the COPScampaign, which took place in the Vosges and Germany. In the meantime,the first European Summer School dedicated to airborne measurementsalso took place and was so successful that it has beendecided to renew the experiment in 2008. Meanwhile, the ADM-AEO-LUS project went well ahead.Aircraft instrumentationFirst EUFAR summer schoolThe 1 st EUFAR summer school, SERAI, was organizedby the Romanian National MeteorologicalAdministration on July 2007 and was basedat Iasi airport, Romania. It aimed at providing atheoretical background to boundary layerdynamics and associated physical processes.The aircraft operator (SAFIRE) also informedthe students about issues specific to airbornemeasurements, such as safety rules, flightplan design and constraints and instrumentcalibration and operation.Firstly, students attended lectures about airborneinstruments and their performanceduring different flight patterns as well as informationabout flight restrictions and other airbornerelated problems provided by SAFIRE.Then, each student had the opportunity to designhis/her own experiments and perform aresearch flight on the SAFIRE instrumentedATR-42. The main achievements of each groupcan be summarised as:• before flight: preparing the flight scenario inaccordance to the guidelines of lecturers andaircraft operators; presenting the objectivesand methods to all students, followed by a discussionwith pilots and lecturers,• during flight: carrying out the necessary inflightmodifications of the scenario,• after flight: preparing a report of the group activitiesincluding quick-look impressions of theacquired data; debriefing, including descriptionof flight plans alteration, quick-look result presentationand difficulties encountered.The collected data were processed and analysedwith the support of experienced users ofairborne facilities. Then, the students wrote ashort scientific report and shared their experimentsand results with the whole group andlecturers. During each step, students were helpedby the lecturers and the SAFIRE crew. Thewhole flight preparation, execution anddebriefing was interactive, thanks to directcontacts with pilots, aircraft operators, andscientific experts.This summer school was both a good trainingexperiments but also a great opportunityfor knowledge exchange and scientificdiscussions. 1SAFIRE participation to the COPS campaignCNRS, Météo-France and CNES jointly operate3 research aircrafts under the SAFIRE project(Service des Avions Français Instrumentéspour la Recherche en Environnement). TwoSAFIRE aircrafts (an ATR42 and a Falcon 20)took part in July 2007 in the internationalresearch campaign COPS (Convective andOrographically–induced Precipitation Study)to study the convection above the Black-Forestand the Vosges.The Falcon 20 flew during 55 hours and wasequipped with a LEANDRE2 lidar (a powerfullaser operating in visual wave-length, detectingatmospheric water vapour). The flightsplans above the studied area were following agrid, at high altitude. The lidar, through adown-looking window, provided importantinformation on the status of the atmospherebefore the convection initiation. The Flaconalso launched about 20 dropsondes (sensorsunder a parachute), which send in real time theinformation of pressure, temperature, humidityand wind of the crossed air.The ATR42 flew 10 hours in the stratiform cloudswhich subsist after convective events. Theflights were dedicated to inter-comparison ofthe measurements of super-cooled water dropletsbetween ground radars and the aircraft.In conclusion, the SAFIRE aircraft brought complementarydata to the international community(german, english, dutch…) which willcontribute to better understand this region'sthunderstorms, and thus, improve the localweather forecasts. 2Integration of the newCAROLS radiometer onthe ATR 42 aircraftSAFIRE is a joint unit of CNRS / Météo-France /CNES which operates 3 instrumented aircrafts,including Météo-France’s instrumentedATR 42. This ATR can be equipped with existingbut also with newly developed instruments,such as the CAROLS (CooperativeAirborne Radiometer for Ocean and LandStudies) radiometer. This radiometer will beused, in particular, during the preparatorycampaign of the satellite SMOS (Soil Moistureand Ocean Salinity, of ESA).This new L-band microwave radiometer (developedby CETP) has been installed for the firsttime on the ATR in September 2007. Two 1.5meters high antennas have been fixed on theATR fuselage. These very sensitive antennashad to be placed outside the fuselage in sucha way as not to impede on the aircraftmanoeuvrability. One antenna pointed atNadir (to the ground) and the other one at 35°,giving a crossing of data. The radiometer canbe coupled or not with the "Storm" weatherradar. SAFIRE carried out the design of theradar integration inside the aircraft as well asthe certification of the entire installation.CAROLS estimates ocean salinity and soilmoisture. In the coming years, the ATR will participateto many scientific campaigns with thisnew radiometer. Indeed, soil moisture contentis an important factor in the meteorologicalphenomena initiation whose study is thereforefundamental. 348 . Research and development: annual report 2007

Students and lecturers together on Iasiairport (Romania), in July 2007, nearthe ATR42 aircraft from Meteo-Franceand operated by Safire.1The ATR42 and the Falcon 20 operated bySAFIRE on Baden Airpark airport, in July 2007,during the COPS campaign.23Agendaand plansfor MOZAICand IAGOS CAROLS’ installation in the ATR cabin (the antenna hasa temperature regulation provided by the yellow cover)4Infrastructure for routine observationof the atmospheric chemistry from civilian aircraftsIAGOS aims to monitor large scale troposphericchemistry using air-borne in situ observationsfrom civilian Airbus aircrafts. It relies onthe experience gained since 1994 from theMOZAIC research programme and preparesthe transition into a sustainable infrastructurewith enhanced measurement capabilities,global coverage, and real timetransmission. IAGOS is part of IGACO (WMOAtmospheric Chemistry monitoring) for thedetection of long term changes and it alsomeets the requirements of future regionalscale Air Quality forecasting centres steeredby the European initiative GMES (GlobalMonitoring for Environment and Security).CNRM and DSO (management of operationalobservation) designed a real time data distributionsystem similar to the AMDAR one(Aircraft Meteorological Data Relay), whichcollects air-borne meteorological observationsfor weather forecasting. In 2007, it wasdecided to defined a new on-board equipmentto act as an interface between the chemistryinstruments (ozone, water vapour,nitrogen oxides, carbon monoxide anddioxide, droplets and aerosol) and the aircraft49 . Research and development: annual report 2007communication systems. This apparatusmust be easily and cheaply fitted inside differentkind of aircrafts and to be able to evolvewith a future air analyzing instrumentation.At the end of 2007, FP7 decided to supportthe preparatory phase of IAGOS that will startin September 2008 and will define the legal,economical and technical structure of theinfrastructure. 4

On site instrumentation and teledetectionRetrieval of the three-dimensional wind fieldfrom the French operational weather radarsin the frame of the FLYSAFE projectThe French ARAMIS network is currently beingupgraded with Doppler capacities. Thisupgrade will equip all radars with Dopplercapacities in order to obtain radial velocitymeasurements at high-resolution (1 km²) inprecipitating areas as far as 250 km awayfrom the radars. The Doppler upgrade of the24 operational radars should be completedby the end of 2008. At the end of 2007, thenetwork was composed of 15 Dopplerradarswhose data are about to be assimilatedby the AROME model. Several tests havealready demonstrated the positive impact ofthese measurements on the quality of forecasts.Doppler velocities are in general difficult tointerpret because radars only measure theprojection of the wind vector along the beamaxis. The values of radial velocities are thereforedependent on the wind field characteristicsbut also pon the relative position of theradar and on the precipitation system. With anetwork of Doppler radars with overlappingareas, the wind vector (u,v,w) can be retrieved.In that context, a real-time demonstratorhas been implemented in northern France. Inthe frame of the FLYSAFE project, a mesoscaledomain (size: 320 x 320 km², horizontal resolution:2.5 km) has been defined encompassingthe Orly and Charles-de-Gaulle airports.Doppler velocities from 6 radars (Trappes,Abbeville, Arcis, Falaise, Avesnes et Bourges)were concentrated, pre-processed and combinedin real-time every 15 minutes.Many different precipitation systems havebeen analysed (frontal and stratiform systems,squall lines, …).The results obtained in the frame of this workhave demonstrated that very consistent informationcould be got about the mesoscalestructure of the three-dimensional flow in precipitationareas. The reconstructed windfields have been evaluated by comparisonwith wind profilers and by numerical simulations,where the reference wind field is perfectlyknown.In that context, results from the real-timedemonstrator have lead the Radar users’group of Météo-France to recommend theoperational implementation of a nationalthree-dimensional reflectivity and wind fieldmosaic (operational in 2009). 5Meteorologicalmeasurementsduring the CirenecampaignThe CIRENE campaign, implemented byLOCEAN in the Indian Ocean by 55° E-80° E,10° S-3° S, was launched to better understandthe ocean-atmosphere coupling at intraseasonalscale and to explain sea surfacetemperature variability mechanisms, and itsinfluence on the atmospheric column.This variability influences the monsoon, andcan contribute to the formation of El Nino.Closely linked to the VASCO campaign thatimplemented Aeroclipper and pressurisedballoons from the Seychelles Island, theCIRENE campaign took place aboard theFrench Research Vessel Le Suroît in Januaryand February 2007. CNRM participated to thiscampaign together with CETP and DT/INSUfor the implementation of turbulent heat andlatent fluxes and precipitations measurementsaboard IFREMER research vessels. Thisinstrumentation was composed of turbulence,temperature, humidity, pressure, andradiatives fluxes measurements, usuallyduplicated to increase reliability. The set upwas the same as the one on the Frenchresearch vessel l’Atalante during the 2006AMMA/EGEE campaign, but it has beennecessary to set a special 11 metres mast tomeasure wind an radiative fluxes in goodconditions, thus reducing the vessel structureinfluence.In order to document atmospheric verticalstructure, CNRM made between 2 and 8radiosoundings; all transmitted in real time tothe Global Transmission System. This datasetwill contribute to a better understanding ofatmospheric phenomena in this area.650 . Research and development: annual report 2007

56 Horizontal and vertical cross-sections at 2 500 m obtainedby combining the data from Trappes, Arcis and Abbevilleon the 23 June 2005 at 1630 UTC during a severe convectiveepisode. The domain, centered on Trappes, has an extensionof 160 x 160 km² and a resolution of 2.5 km. The reflectivityfield is shown in colors. The arrow-less areas correspondto precipitation-free areas where no velocity data are available.Despite the rather large distance between radars, it can beseen that convective scale structures can be recovered. The French research vessel Le Suroîtwith it the 11 metre mast in Victoria harbour(Seychelles islands). On the bow,an Aeroclipper gondola readyfor an instrumented mast inter comparison.51 . Research and development: annual report 2007

Instrumentation duringthe COPS campaignThe German Research Foundation provides base funding for Quantitative PrecipitationForecast Researchs. One of the key action of this program was the Convective andOrographically induced Precipitation Study (COPS), an international field campaign. Thefield experiment was set in South-West Germany and South-East France (mainly Vosges andthe Black Forest) from June to August 2007. Several French laboratories took part in thiscampaign like Laboratoire d’Aérologie, Institut Pierre-Simon Laplace, IGN, LAMP, SAFIRE,CNRM/GMEI... Among other things, Météo-France developed a super-site instrumentation inMeistratzheim (20 km South of Strasbourg) in July 2007.This super-site was equipped with two surface flux stations recording ground temperatureand moisture, a scintillometer for measures of the surface sensible heat flux over a 3 kmlong horizontal path. To describe the lower layers, a modified ceilometer, a doppler sodarand an UHF wind profiler will be used during the IOP campaign, when 110 radiosondes havebeen launched and incorporated into the data assimilation system of the forecast model.Every days, quicklooks of all of the instruments were sent to the operation centre in BadenBaden, Germany, where a SYNERGIE station had been set. Forecasters of the inter-regionalservice of Météo-France (DIRNE from Strasbourg) also worked on forecasts for the researchersof the campaign and the pilots of aircrafts. This exchange between researchers andforecasters from different European countries happened to be a very fulfilling experience onboth sides.7Preparationof the ADM-AEOLUSspace missionThe wind lidar ADM-AEOLUS space missionof the European Space Agency is in its finalstages of development before the launchnow planned for mid-2009.In 2007, CNRM has continued its work in 3different activities related to the processorsof level 1b (dated and geo-referenced windsuncorrected from pressure and temperatureeffects), 2a (optical products) and 2b (windsthat weather forecasting systems can assimilate).The level 1b processor is now nearlycompleted. As far as level 2a is concerned,CNRM delivered two successive versions ofthe prototype processor. We also started anew activity on the in-flight radiometric calibrationof the instrument required by thelevel 2a processor. Lastly, the developmentof the level 2b processor has progressed incollaboration with the European Centre forMedium-range Weather Forecast, and theDutch weather service KNMI. Our contributionbore mainly on the development of aportable version of the processor dedicatedto weather services that wish to assimilateADM data themselves.The A2D has passed several successfulsteps in 2007 thanks to the hard work of theDLR. Two ground-based campaigns were carriedout, as well as a first airborne campaign.A second airborne campaign isplanned for 2008.An announcement of opportunity was publishedby ESA for the in-flight calibration / validationof the instrument. The AO was basedon a requirement document to which wecontributed through reviews. CNRM submittedan answer based on the work plan proposedand supported by CNES. The answer ismade of 5 different proposals from 5 Frenchresearch institutes. CNRM is responsible fortheir coordination. 852 . Research and development: annual report 2007

7 Radiosonde balloon in Meistratzheim8Aeolus transmitter laser.The two amplifier units(the two rectangular blocks)each contain eight laser diode stacks.53 . Research and development: annual report 2007

Communicationand promotionCNRM communicates and promotes its activities in the field ofresearch. Two major events took place in 2007: the first one consistedin answering the numerous questions around climate changes, theother one was the creation ofCNRM scientific publications.an access free archive to promoteCommunicationStrengthening the general awarenessabout climate changeThe publication of the GIEC 4 th report, followedby the Nobel prize awarded to climate experts,made the headlines in 2007. In this context,scientists from Météo-France were very muchsolicited.Many popular scientific magazines (Science &Avenir, Pour la Science, La Recherche, Science& Vie, …) released a special "climate change"issue in 2007. Papers written by CNRM orDCLIM scientists were systematically submittedand accepted by the editorial committeeof these magazines. The non-specializednational press, whether newspapers, televisionor radio, followed suit and numerousinterviews and reports were made. As anexample, let us cite notably the interventionsby S. Planton, by P. Delécluse or by E. Brun inseveral successful radio or television programs.(« Téléphone sonne » or « CO 2 monamour » on France Inter, « C dans l’Air » onFrance 5, special program at 20 h 50 onFrance 3, television and radio interviews onTF1, France 2, RTL, Europe 1, France Info, …).CNRM researchers also took part in about 80conferences on these themes, the debatesbeing sometimes either very scientific or,sometimes, for the general public.In term of internal communication, severalevents were organized on the site of theMétéopole : presentation of first GIEC workinggroup report at the CIC (250 persons), 5 CNRMseminaries on this topic (about 100 personsattending every session), talks following theprojections of the film « An Inconvenient Truth ».Efforts of internal training were also followedby the organization of 2 training sessionsabout "climate changes" in cooperation withENM.All these actions led to a better understandingof the work carried by Météo-France on climate,and to make our fellow citizens sensitiveto planet warming. This step will go on in2008, with notably for the first time, an externaltraining course on the same topic. 1The new open access archive HAL Météo-FranceThe open access archive HAL Météo-Francehas been implemented on the 3 rd October2007. This electronic repository of full-textMétéo-France scientific publications gatherstogether articles published in peer-reviewedjournals, PhD theses, “habilitations à dirigerdes recherches” and conference proceedings.It is a subset of HAL, an interdisciplinaryonline archive initiated by the CentreNational de la Recherche Scientifique(CNRS). HAL Météo-France perpetuates thescientific production of Météo-France andincreases its value. With this creation,Météo-France is joining the internationalmovement for free access to scientificresearch results. As all other open archives,HAL Météo-France provides an easier accessto the most recent scientific literature forresearchers of the countries of the South.The documents are deposited by theirauthors, in respect of the publishers copyrightpolicies, with the support of Météo-France librarians. If full-text archiving is notauthorized by the publisher of a journal,only the bibliographic metadata are accessible.A set of explanations and helpresources are available on-line on theMétéo-France Intranet. The implementationof HAL Météo-France is the first step tomodernize the whole Météo-France scientificinformation system. 254 . Research and development: annual report 2007

Serge Planton, Head of Climate Resarchat Météo-France, with Joël Collado (Météo-France/Radio-France), during a lectureabout climate changes during the jazz festival“ Jazz in Marciac “, in August 7 th 2007.Internet access toHAL Météo-France55 . Research and development: annual report 2007

Appendix2007 scientific papers listPapers whose at least one author is evaluated by CNRM and is not seconded appear in clear in the list below.Papers published in rank “ A “ journals (Impact factor > 1)Ahmadov R., C. Gerbig, R. Kretschmer, S. Koener, B.Neininger, A.J. Dolman, C. Sarrat, 2007 : Mesoscalecovariance of transport and CO 2 fluxes: evidencefrom observations and simulations using the WRF-VPRM coupled atmosphere-biosphere model, J.Geophys. Res., 112, D22107, doi:10.1029/2007JD008552.Andersson E, , Holm E, Bauer P., Bejaars A., KellyG.A., McNally A.P., Simmons A.J., Thepaut J.-N. andTompkins A. M., 2007 : Analysis and forecastimpact of the main humidity observing systems. QJ ROY METEOR SOC 133 (627): 1473-1485 Part BJUL 2007.Auer I., Boehm, R., Jurkovic, A., Lipa, W., Orlik, A.,…, Mestre, O., Moisselin, J-M, and al, 2007 : HIS-TALP - historical instrumental climatological surfacetime series of the Greater Alpine Region. INT J CLI-MATOL 27 (1): 17-46 JAN 2007.Auger L. and B. Legras, 2007 : Chemical segregationby heterogenous emissions. AtmosphericEnvironment, 41, 2303-2318.Auligné T, 2007. An objective approach to modellingradiances: application to AIRS biases in satelliteand AMSU-A. Q J ROY METEOR SOC 133 (628):1789-1801 Part A OCT 2007Auligné T, McNally A.P. and Dee D.P. , 2007 :Adaptive bias correction for satellite data in anumerical weather prediction system. Quart. J. R.Met. Soc., 133, 631-642.Auligné T. and McNally A.P., 2007 : Interaction betweenbias correction and quality control. Quart. J.R. Met. Soc., 133, 643-653.Baghdadi N., Aubert M., Cerdan O., FranchistéguyL., Viel C., Martin E., Zribi M. and Desprats J.-F.,2007 : Operational mapping of soil moisture usingsynthetic aperture radar data: application to Touchbasin (France). Sensors Journal, vol. 7, pp. 2458-2483.Baker B. and J.-L. Brenguier, 2007 : Radar and In-Situ Observations of Small Cumulus: PhysicalInterpretations of Radar Bragg Scatter, Quart. J. Roy.Meteorology, 133(628) : 1677 -1692.Baret F., O. Hagolle, B. Geiger, P. Bicheron, B. Miras,M. Huc, B. Berthelot, M. Weiss, O. Samain, J.-L.Roujean et M. Leroy, 2007 : LAI, fAPAR and fCoverCYCLOPES global products derived from VEGETA-TION. Part 1 : Principles of the algorithm, RemoteSensing of Environment, 110, 275-286.Bergot T., E. Terradellas, J. Cuxart, A. Mira, O. Liechti,M. Mueller and N. Woetmann Nielsen, 2007 :Intercomparison of single-column numericalmodels for the prediction of radiation fog. J. Appl.Meteorol., 46, 504-521.Bock O., F. Guichard, S. Janicot, J.-P. Lafore, M.-N.Bouin and B. Sultan, 2007 : Multiscale analysis ofprecipitable water vapor over Africa from GPS dataand ECMWF analyses, Geophys. Res. Lett., 34,L09705, doi : 10.1029/2006GL028039.Boé J., Terray L., Habets F., Martin E., 2007 : Statisticaland dynamical downscaling of the Seine basinclimate for hydrometeorological studies. InternationalJournal of Climatology, DOI:10.1002/joc.1602.Bormann N. and Thepaut J-N., 2007 : Assimilationof MIPAS limb radiances in the ECMWF system. I:Experiments observation with a 1-dimensionaloperator, Q J ROY METEOR SOC 133 (623): 309-327Part B JAN 2007.Bourras D., G. Reverdin, G. Caniaux and S. Belamari,2007 : A nonlinear statistical model of turbulent airseafluxes. Mon. Wea. Rev., 135, (3), 1077-1089,doi : 10.1175/MWR3335.1.Bousquet O., Tabary P. et al., 2007 : On the value ofoperationally synthesized multiple-Doppler windfields - art. no. L22813, GEOPHYS RES LETT 34 (22):22813-22813 NOV 29 2007.Bousserez N., J.-L. Attié, V.-H. Peuch, M. Michou, G.Pfister, D. Edwards, M. Avery, G. Sachse, E. Browelland E. Ferrare, 2007 : Evaluation of MOCAGE chemistryand transport model during the ICARTT/ITOPexperiment, J. Geophys. Res., 112 (D120S42), doi:10.1029/2006JD007595.Buizza R, Cardinali, C. Kelly, G, Thepaut J-N, 2007 :The value of observations. II: The value of observationslocated in singular-vector-based target areas.Q J ROY METEOR SOC 133 (628): 1817-1832 Part AOCT 2007.Burnet F. and Brenguier, J-L, 2007 : ObservationalStudy of the Entrainment-Mixing Process in WarmConvective Clouds, J. Atmos. Sci., 64, 1995-2011.Caballero Y., P. Chevallier, A. Boone, F. Habets andJ. Noilhan, 2007: Calibration of the InteractionSoil Biosphere land-surface scheme on a smalltropical high mountain basin (Cordillera Real,Bolivia). Wat. Res. Research, 43, doi:10.1029/2005WR004490.56 . Research and development: annual report 2007Caballero Y., S. Voirin-Morel, F. Habets, J. Noilhan, P.LeMoigne, A. Lehenaff, A. Boone, 2007: Hydrologicalof the Adour-Garonne river basin to climatechange. Water Resources Research, 43, Doi: 101029/2005WR004192.Calvet J.-C., A. Gibelin, J. Roujean, E. Martin, P.LeMoigne, H. Douville and J. Noilhan, 2007 : "Pastand future scenarios of the effect of carbon dioxide onplant growth and transpiration for three vegetationtypes of southwestern France", Atmos. Chem. Phys.Discuss., 7, 4761-4779.(http : //www.copernicus.org/EGU/acp/acpd/7/4761/acpd-7-4761.pdf).Cardinali C, , Buizza R, Kelly G., Shapiro M., Thepaut, J-N., 2007 : The value of observations. III: Influence ofweather regimes on targeting. Q J ROY METEOR SOC133 (628): 1833-1842 Part A OCT 2007.Cariolle D. and H. Teyssèdre, 2007 : a revised linearozone photochemistry parameterization for use intransport and general circulation models: multiannualsimulations.Atmospheric Chemistry andPhysics, Vol 7, Pages : 2183-2196.Catry B., J.-F. Geleyn, M. Tudor, P. Bénard and A.Trojakova, 2007 : Flux-conservative thermodynamicequations in a mass-weighted framework. Tellus,59A, pp. 71-79.Chaboureau J.-P., Tulet P., Mari C., 2007. Diurnalcycle of dust and cirrus over West Africa as seenfrom Meteosat Second Generation setellite and aregional forecast model. Geophys. Res. Lett., 34,L02822, doi: 10.1029/2006GL027771.Chauvin F. and S. Denvil, 2007 : Changes in severeindices as simulated by two French coupled globalclimate models. Global and Planetary Change, 57(1-2), 96-117.Chen J., R. J. Griffin, A. Grini and P. Tulet, 2007 :Modeling secondary organic aerosol formationthrough cloud processing of organic compounds.Atmos. Chem. Phys., 7, 5343-5355.Chevalier A., F. Gheusi, R. Delmas, C. Ordóñez, C.Sarrat, R. Zbinden, V. Thouret, G. Athier and J.-M.Cousin, 2007 : Influence of altitude on ozone levelsand variability in the lower troposphere: a surfacemeasurementsbased study for western Europe overthe period 2001-2004. Atmos. Chem. Phys., 7, 4311-4326.Chevrot S., Sylvander M., Benahmed S., PonsollesC. Lefevre J.-M., Paradis D., 2007 : Source locationsof secondary microseisms in western Europe:

Evidence for both coastal and pelagic sources. JGEOPHYS RES-SOL EA 112 (B11): - NOV 1 2007Chosson F., J.-L. Brenguier and L. Schüller, 2007 : Entrainment-mixingand radiative transfer simulation inboundary-layer clouds. J. Atmos. Sci., 64, 2670-2682.Clark H.L., M.-L. Cathala, H. Teyssèdre, J.-P. Cammasand V.-H. Peuch, 2007 : Cross-tropopause fluxes ofozone using assimilation of MOZAIC observationsin a global CTM, Tellus, 59B, 39-49.Conil S., H. Douville, S. Tyteca, 2007, "The relativeroles of soil moisture and SST in climate variabilityexplored within ensembles of AMIP-type simulations".Climate Dyn., 28, 125-145, doi: 10.1007/s00382-006-0172-2.Courault D., Drobinski Ph., Brunet Y., Lacarrere P.,Talbot C., 2007 : Impact of surface heterogeneity ona buoyancy-driven convective boundary layer inlight winds, Boundary layer meteorology, doi:10.1007/s10546-007-9172-y.Couvreux F., F. Guichard, V. Masson and J.L.Redelsperger, 2007 : Negative water vapour skewnessand dry tongues in the convective boundarylayer: observations and LES budget analysis. BoundaryLayer Meteorology, 123,269-294.Cuvelier C., P. Thunis, R. Vautard, M. Amann, B.Bessagnet, M. Bedogni, R. Berkowicz, F. Brocheton, P.Builtjes, C. Carnavale, A. Coppalle, B. Denby, G.Douros, A. Graf, O. Hellmuth, C. Honore, J. Jonson, A.Kerschbaumer, F. de Leeuw, E. Minguzzi, N.Moussiopoulos, C. Pertot, V.H. Peuch, G. Pirovano, L.Rouil, F. Sauter, M. Schaap, R. Stern, L. Tarrason, E.Vignati, L. Volta, L. White, P. Wind, A. Zuber, 2007 :CityDelta, a model intercomparison study to explorethe impact of emission reductions in European citiesin 2010, Atmos. Env., ATMENV-D-06-00252R1, Atmos.Env., 41(1), 189-207.Decharme B. and H. Douville, 2007: "Global validationof the ISBA Sub-Grid Hydrology". Climate Dyn.,doi: 10.1007/s00382-006-0216-7.Delon C., C.E. Reeves, D.J. Stewart, D. Serça, R.Dupont, C. Mari, J.-P. Chaboureau and P. Tulet, 2007: Nitrogen Oxide biogenic emissions from soils:impact on NOx and ozone formation in West Africaduring AMMA (African Monsoon Multidis-ciplinaryAnalysis). Atmos. Chem. Phys. Discuss., 7, 15155-15188.Descamps L. and O. Talagrand, 2007: On some aspectof the definition of initial conditions for ensemble prediction.Mon. Wea. Rev., 135, 3260-3272.Descamps L., D. Ricard, A. Joly and P. Arbogast,2007 : "Is a Real Cyclogenesis Case Explained byGeneralized Linear Baroclinic Instability? ". J. Atm.Sci., 64, 4287-4308.Donlon C., Robinson I., Casey K., Vazquez-Cuervo J.,Armstrong E., Arino O., Gentemann C., May D.,LeBorgne P. and al, 2007 : The global ocean dataassimilation experiment high-resolution sea surfacetemperature pilot project. BAMS, Volume: 88Issue: 8 Pages: 1197-1213.Douville H., S. Conil, S. Tyteca, A. Voldoire, 2007 : Soilmoisture memory and West African monsoon predictability:artefact or reality? Climate Dyn., doi: 10.1007/s00382-006-0207-8.Drobinski Ph., P. Carlotti, JL. Redelsperger, RM. Banta,V. Masson, RK. Newsom, 2007 : Numerical and experimentalinvestigation of the neutral atmosphericsurface layer. American Meteorological Society, 64,137-156, JAS doi: 10.1175/JAS3831.1.Drobinski Ph. , F. Said, G. Ancellet, J. Arteta, P.Augustin, S. Bastin, A. Brut, J.L. Caccia, B.Campistron, S. Cautenet, A. Colette, I. Coll, U.Corsmeier, B. Cros, A. Dabas, H. Delbarre, A. Dufour,P. Durand, V. Guénard, M. Hasel, N. Kalthoff, C.Kottmeier, F. Lasry, A. Lemonsu, F. Lohou, V. Masson,L. Menut, C. Moppert, V.H. Peuch, V. Puygrenier, O.Reitebuch, R. Vautard, 2007 : Regional transportand dilution during high pollution episodes in southernFrance: Summary of findings from theESCOMPTE experiment. J. Geophys. Res., 112,D13105, doi: 10.1029/2006JD007494.Drobinski Ph. , R. Steinacker, H. Richner, K.Baumann-Stanzer, G. Beffrey, B. Benech, H. Berger,B. Chimani, A. Dabas, M. Dorninger, B. Dürr, C.Flamant, M. Frioud, M. Furger, I. Gröhn, S. Gubser, T.Gutermann, C. Häberli, E. Häller-Scharnhost, G.Jaubert, M. Lothon, V. Mitev, U. Pechinger, M.Piringer, M. Ratheiser, D. Ruffieux, G. Seiz, M.Spatzierer, S. Tschannett, S. Vogt, R. Werner, G.Zängl, 2007 : Föhn in the Rhine Valley during MAP: Areview of its multiscale dynamics in complex valleygeometry, 2007: Quart. J. Roy. Meteor. Soc. , 133,897-916 2007Errico RM., Bauer P. and Mahfouf J-F, 2007 : Issuesregarding the assimilation of cloud and precipitationdata, J ATMOS SCI 64 (11): 3785-3798.Escorihuela M.J., Y. Kerr, P. de Rosnay, J. P. Wigneron,J.-C. Calvet and F. Lemaître, 2007 : A Simple Model ofthe Bare Soil Microwave Emission at L-Band, /IEEETrans. Geosc. //Remote Sens., Vol. 45, No. 7, pp.1978-1987.Escorihuela M.J., P. de Rosnay, Y. Kerr and J.-C. Calvet,2007 : Influence of bound water relaxation frequencyon soil moisture measurements, IEEE Trans.Geosc. RemoteSens. Vol. 45, No. 12, pp. 4067-4076.Felder M., P. Poli et J. Joiner, 2007 : Errors induced byozone field horizontal inhomogeneities into simulatednadir-viewing orbital backscatter UV measurements.Jour. Geophys. Res. (Atmospheres). Vol. 112,No. D1, D01303 10.1029/2005JD006769.Friedrich K., U. Germann, J. Gourley and P. Tabary,2007 : Effects of radar beam shielding on rainfallestimation for the polarimetric C-band radar. JATMOS OCEAN TECH 24 (11): 1839-1859 NOV 2007.Geer A.J., W.A. Lahoz, D.R. Jackson, D. Cariolle, J.PMcCormack, 2007 : Evaluation of linear ozone photochemistryparametrizations in a stratosphere-tropospheredata assimilation system. ATMOS CHEMPHYS 7: 939-959 FEB 21 2007.Gibert F., J. Cuesta, J.-I. Yano, N. Arnault and P.-H.Flamant, 2007 : On the correlation between convectiveplume up and downdrafts, lidar reflectivity anddepolarization ratio. Boundary Layer Meteorol.,125(3) : 553-573, déc 2007.Gourley J.-J., P. Tabary, J. Parent du Chatelet, 2007:Empirical estimation of attenuation from differentialpropagation phase measurements at C-band, J.Appl. Meteor., 46, No. 3, 306 - 31757 . Research and development: annual report 2007Gourley J.-J., P. Tabary, J. Parent du Chatelet, 2007:A fuzzy logic algorithm for the separation of precipitatingfrom non-precipitating echoes using polarimetricradar, J. Atmos. Oceanic Technol., Vol. 24,No. 8, 1439-1451.Guemas V., D. Salas-Mélia (2007) : Simulation of theAtlantic meridional overturning circulation in anatmosphere-ocean global coupled model. Part I: amechanism governing the variability of ocean convectionin a preindustrial experiment, Climate Dynamics.doi: 10.1007/s00382-007-0336-8. (http://www.springerlink.com/content/b67l67835n0k7650).Guemas V., D. Salas-Mélia (2007) : Simulation of theAtlanticmeridionaloverturning circulation in an atmosphere-oceanglobal coupled model. Part II : weakeningin a climate change experiment: a feedback mechanism,Climate Dynamics. doi: 10.1007/s00382-007-0328-8.(http://www.springerlink.com/content/6322236q88285k37)Hallegatte S., 2007 : The use of synthetic hurricanetracks in risk analysis and climate change damageassessment, J. Appl. Meteor. Clim., 46, 1956-1966.Hallegatte S., J.-C. Hourcade and P. Ambrosi, 2007a :Using climate analogues for assessing climatechange economic impacts, Climatic Change, 82, 47-60.Hallegatte S., J.-C. Hourcade and P. Dumas, 2007b :Why economic dynamics matter in assessing climatechange damages: illustration on extreme events,Ecological Economics, 62, 330-340.Haman K., S. Malinowski, M. Kurowski, H. Gerber,and J.-L.Brenguier, 2007 : Small scale mixing processesat the top of a marine stratocumulus – a casestudy. QJRMS, Volume: 133 Issue: 622 Pages: 213-226Part: A.Healy SB, JR Eyre, M. Hamrud and J.-N. 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Joly M., A. Voldoire, H. Douville, P. Terray and J.-F.Royer, 2007 : African monsoon teleconnec-tionswith tropical SSTs : validation and evolution in aset of IPCC4 simulations, Climate Dynamics, doi:10.1007/s00382-006-0215-8 URL :http://dx.doi.org/10.1007/s00382-006-0215-8Kelly G, JN Thepaut, R. Buizza and C. Cardinali,2007 : The value of observations. I: Data denialexperiments for the Atlantic and the Pacific. Q J ROYMETEOR SOC 133 (628): 1803-1815 Part A Oct2007Lahoz W.A., A.J. Geer, S. Bekki, N. Bormann, S.Cec-cherini, H. Elbern, Q. Errera, H.J. Eskes, D.Fonteyn, D.R. Jackson, B. Khattatov, S. Massart, V.-H. Peuch, S. Rharmili, M. Ridolfi, A. Segers, O.Talagrand, H.E. Thornton, A.F. Vik et T. VonClarman, 2007 : The Assimilation of Envisat data(ASSET) project, Atmos. Chem. Phys., 7, 1773-1796.(http ://www.copernicus.org/EGU/acp/acp/recent_papers.html).Legrand M., S. Preunkert, M. Schock, M.Cerqueira, A. Kasper-Giebl, J. Afonso, C. Pio, A.Gelencsér and I. 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Swingedouw D, P. Braconnot, P. Delecluse, E.Guilyardi and O. Marti, 2007 : Quantifying theAMOC feedbacks during a 2xCO(2) stabilizationexperiment with land-ice melting. CLIM DYNAM 29(5): 521-534 OCT 2007.Swingedouw D, P. Braconnot, P. Delecluse, E.Guilyardi and O. Marti, 2007 : The impact of globalfreshwater forcing on the thermohaline circulation:adjustment of North Atlantic convection sites in aCGCM. CLIM DYNAM 28 (2-3): 291-305 FEB 2007Tabary P., 2007 : The new French radar rainfall product.Part I: methodology, Wea. Forecasting, Vol.22, N° 3, 393 - 408.Tabary P., J. Desplats, K. Do Khac, F. Eideliman, C.Gueguen and J.-C. Heinrich, 2007 : The new Frenchradar rainfall product. Part II: Validation, Wea.Forecasting, Vol. 22, No. 3, 409 - 427.Terray P., F. Chauvin, H. Douville, 2007 : Impact ofsoutheast Indian Ocean sea surface temperatureanomalies on monsoon-ENSO-dipole variability ina coupled ocean-atmosphere model. 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Bidet, 2007 :Assistance météorologique à la prévention et à lalutte contre les feux de forêts en zone méditerranéenne.La Météorologie, 8 e série, n° 56, février2007, pp 22-26.Martin E., V. Ducrocq, A. Joly, B. Joly, O. Nuissier, P.Quintana Seguí, D. Ricard, Sevault F., Somot S., P.Drobinsky, 2007 : La Méditerranée, région témoin: de Cyprim à Hymex, La Houille Blanche, N° 6 -2007, 90-96.Massart S., A. Piacentini, D. Cariolle, L. El Amraoui,N. Semane, 2007 : Assessment of the quality of theozone measurements from the Odin/SMR instrumentusing model assimilation. Can. J. Phys., 85,1209-1223, doi:10.1139/P07-124.

Moisselin J.-M. et S. Jourdain, 2007 : Long-term datarescue and use. La Houille Blanche (1) : 33-38 2007.Navarre J-P. J. Meyssonnier and A. Vagnon, 2007 :3D numerical model of snow deformation withoutfailure and its application to cold room mechanicaltests, Cold Regions Science and Technology,Vol 50 (2007) 3-12.Planton S., 2007 : Réchauffement climatique : attributionet recherche des causes, série trimestrielledes Annales des Mines, Responsabilité et Environnement,n° 47, pages 12-17.Planton S. et L. Terray, 2007 : Détection et attributionà l'échelle régionale : le cas de la France, LaMétéorologie, 8 e série, n° 58, pp25-29.Roquelaure S. and T. Bergot, 2007 : Seasonal sensitivityon COBEL-ISBA local forecast system for fog andlow clouds. Journal of Pure and Applied Geophysics,special issue on fog and low clouds. 164.Royer J.-F., H. Douville, 2007 : le forçage climatique- cause naturelle et cause anthropique, hors-sériede Sciences et Avenir, n° 150, pp 73-76.Sacre C, JM Moisselin, M. Sabre, J.-P. Flori and B.Dubuisson, 2007 : A new statistical approach toextreme wind speeds in France. J WIND ENG INDAEROD 95 (9-11): 1415-1423 OCT 2007.Salas-Mélia D., C. Genthon, O. Arzel, C. Cassou, V.Guemas, G. Krinner, M. Minvielle et D. Swingedouw,2007 : Régions polaires, cryosphère et circulationthermohaline. Que nous ont appris lessimulations du 4 e rapport d'évaluation du GIEC ?,La Météorologie, 8 e série, n° 56, fév. 2007, pp 33-39.Tchiguirinskaia I., D. Schertzer, S. Lovejoy and J.-M.Veysseire, 2007 : Wind extremes and scales: Multifractalinsights and empirical evidence. WindEnergy : 99-104.Wagner W., P. Pampaloni, G. Blöschl, J.-C. Calvet, B.Bizzarri, J.-P. Wigneron, Y. Kerr, 2007 : OperationalReadiness of Microwave Remote Sensing of SoilMoisture for Hydrologic applications. NordicHydrology, Vol. 1, N° 1, pp. 1-20.Contribution to books or reportsAlcamo, J., J.M. Moreno, B. Novaky, M. Bindi, R.Corobov, R.J.N. Devoy, C. Giannakopoulos, E. Martin,J.E. Olesen, A. Shvidenko, 2007 : Climate Change2007: Impacts, Adaptation and Vulnerability.Contribution of Working Group II to the FourthAssessment Report of the Intergovernmental Panelon Climate Change, M.L. Parry, O.F. Canziani, J.P.Palutikof, C.E. Hanson, P.J. van der Linden, Eds.,Cambridge University Press, Cambridge.Apicella, L., F. Tallet, S. Hallegatte, F. Nadaud, 2007,Aléas climatiques, aléas économiques : les effets duclimat sur l'activité économique en France, dossierde la Note de Conjoncture de l'INSEE, juillet 2007.Cerveny, R., V.D. Belitskaya, P. Bessemoulin, M.Cortez, C. Landsea and T.C. Peterson, 2007: A NewWestern Hemisphere 24-Hour Rainfall Record. WMOBulletin, 56(3), 212-215, July 2007.Faure G., S. Westrelin, 2007 : A new Météo-FranceNWP system over the southwest Indian ocean. WGNEBlue Book.Le Borgne P, A. Marsouin, F. Orain, H. Roquet, A. Coatand Y. Guichoux, 2007 : Implementation of a finescale SST analysis over the Atlantic Ocean , MERSEA-WP02-MF-STR-002-1A, 41p.Lavanant L., 2007 : Radiance spatial distribution inIASI sounder for analysis. Rapport CNES CalVal IASIlevel1 phaseA.Papers are available at the following address ( http://intramet.meteo.fr/bibliotheque/ )using the item "documentations scientifiques et techniques".60 . Research and development: annual report 2007

Theses defended in 2007Auligné T., 2007 : Assimilation variationnelle desobservations de sondeurs infrarouges hyperspectraux: correction de biais et détection nuageuse,thèse de doctorat de l'université Paul-Sabatier, disciplineOcéan Atmosphère et Environnement, soutenuele 8 juin 2007.Caumont O., 2007 : Simulation et assimilation dedonnées radar pour la prévision de la convectionprofonde à fine échelle, thèse de doctorat de l'universitéPaul-Sabatier, discipline Océan Atmosphèreet Environnement, soutenue le 4 décembre 2007.Descamps L., 2007 : Définition des conditions initialesdes prévisions d'ensemble. Liens avec l'assimilationde données, thèse de doctorat del'université Paris VI, discipline Sciences de l'environnementd'Île de France, soutenue le 29 octobre2007.Geoffroy O., 2007 : Modélisation LES des précipitationsdans les nuages de couche limite et paramétrisationpour les modèles de circulation générale,thèse de doctorat de l'université Paul-Sabatier, disciplineOcéan Atmosphère et Environnement, soutenuele 22 mai 2007.Gibelin A-L, 2007 : Cycle du carbone dans un modèlede surface continentale : Modélisation, validation etmise en œuvre à l'échelle globale, thèse de doctoratde l'université Paul-Sabatier, discipline OcéanAtmosphère et Environnement, soutenue le 9 mai2007.Guidard V, 2007 : Assimilation multi-échelle dans unmodèle météorologique régional, thèse de doctoratde l'université Paul-Sabatier, discipline OcéanAtmosphère et Environnement, soutenue le 23 octobre2007.Lebeaupin C., 2007 : Étude du couplage océnaatmosphèreassocié aux épisodes de pluie intenseen région méditerranéenne, thèse de doctorat del'université Paul-Sabatier, discipline Océan Atmosphèreet Environnement, soutenue le 19 décembre2007.Munoz-Sabater J., 2007 : Assimilation de donnéesde télédétection pour le suivi des surfaces continentales: Mise en œuvre sur un site experimental, thèsede doctorat de l'université Paul-Sabatier, disciplineOcéan Atmosphère et Environnement, soutenue le13 avril 2007.Pigeon G., 2007 : Les échanges surface-atmosphèreen zone urbaine - projets CLU-ESCOMPTE et CAPI-TOUL, thèse de doctorat de l'université Paul-Sabatier,discipline Océan Atmosphère et Environnement,soutenue le 29 mai 2007.Rivière O., 2007 : Prévisibilité de l'écoulement atmosphériqueaux échelles synoptiques : influence desnon-linéarités et de l'humidité, thèse de doctorat del' École nationale des Ponts et Chaussées, disciplineMathématique informatiques, soutenue le 19 décembre2007.Roquelaure S., 2007 : Prévision d'ensemble localedes brouillards et nuages bas à l'aéroport internationalde Roissy - Charles-De-Gaulle, thèse de doctoratde l'université Paul-Sabatier, discipline OcéanAtmosphère et Environnement, soutenue le 3 décembre2007.Rousset F., 2007 : Modélisation des bilans de surfaceet des débits sur la France, application à la prévisiondes débits, thèse de doctorat de l'universitéPaul-Sabatier, discipline Océan Atmosphère etEnvironnement, soutenue le 6 juillet 2007.Sandu I., 2007, Impact de l'aérosol sur le cycle de viedes nuages de couche limite, thèse de doctorat del'université Paul-Sabatier, discipline OcéanAtmosphère et Environnement, soutenue le 8novembre 2007.Sohne N., 2007 : Validation des prévisions denuages et de précipitations à mésoéchelle par l'observationsatellite, thèse de doctorat de l'universitéPaul-Sabatier, discipline Océan Atmosphère etEnvironnement, soutenue le 23 novembre 2007.Tomas S., 2007 : Modélisation et étude expérimentalede la turbulence au sein des couches limitesatmosphériques, thèse de doctorat de l'universitéPaul-Sabatier, discipline Océan Atmosphère etEnvironnement, soutenue le 30 janvier 2007.Zaïri E.-P., 2007 : Cycle de l'eau des systèmesconvectifs Ouest Africains : préparation à l'exploitationdes mesures radar Xport dans AMMA par simulation,thèse de doctorat de l'universitéPaul-Sabatier, discipline Océan Atmosphère etEnvironnement, soutenue le 29 janvier 2007.« Habilitation à diriger des recherches » defended in 2007Desroziers G., 2007 : mise en œuvre, diagnostic etoptimisation des schémas d'assimilation de données,habilitation à diriger des recherches auprès del’Université Toulouse III, discipline Physique del'Atmosphère, soutenue le 11 mai 2007.61 . Research and development: annual report 2007

GlossaryOrganismsAASQA Associations Agréées de Surveillance de la Qualité de l'AirCEDRE Centre de Documentation, de Recherche et d'Expérimentationssur les pollutions accidentelles des eauxCEPMMT Centre Européen pour les Prévisions Météorologiques à Moyen TermeCEREA Centre d'Enseignement et de Recherche en EnvironnementAtmosphériqueCERFACS Centre Européen de Recherche et de Formation Avancée en CalculScientifiqueCESBIO Centre d' Etudes Spatiales de la BIOsphèreCNES Centre National d'Etudes SpatialesCNRS Centre National de la Recherche ScientifiqueDLR Deutsche zentrum fur Luft und RaumfahrtESA European Space Agency (Agence Spatiale Européenne)EUMETNET EUropean METeorological NETworkEUMETSAT EUropean organisation for the exploitation of METeorological SATellitesHADLEY CENTER Centre Britannique de Recherche sur le Changement ClimatiqueIFREMER Institut Français de Recherche pour l'Exploitation de la MERIGN Institut Géographique NationalIMFT Institut de Mécanique des Fluides de ToulouseINSU Institut National des Sciences de l'UniversKNMI Koninklijk Nederlands Meteorologisch Instituut (Institutroyal météorologiquedes Pays-Bas)MEDAD Ministère de l'Ecologie, du Développement et de l'Aménagement DurableMERCATOR Océan GIP visant à la mise en œuvre d'un système opérationnel de prévisionocéanographique globalNCEP National Centers for Environmental PredictionOMM Organisation Météorologique MondialeONERA Office National d'Etudes et de Recherches AérospatialesSPOT Satellite Pour l'Observation de la TerreUKMO (MetOffice) United Kingdom Meterological OfficeLaboratories or research/development teamsCEN Centre d'Etudes de la NeigeCETP Centre d'Étude des environnements Terrestre et PlanétaireCMM Centre de Météorologie MarineCMS Centre Météorologie SpatialeCNRM Centre National de Recherches MétéorologiquesENM/UFR Ecole Nationale de la Météorologie/Unité de Formation et de RechercheGAME Groupe d'études de l'Atmosphère MétéorologiquEIPSL Institut Pierre-Simon-LaplaceLA Laboratoire d'AérologieLaMP Laboratoire de Météorologie PhysiqueLCPC Laboratoire Central des Ponts et ChausséesLISA Laboratoire Interuniversitaire des Systèmes AtmosphériquesLOCEAN Laboratoire d'Océanographie et du Climat : Expérimentations etApproches NumériquesNASA National Aeronautics and Space AdministrationSAFIRE Service des Avions Français Instrumentés pour la Recherche enEnvironnementSPEA Simulation Physique des Ecoulements AtmosphériquesNational or european programms or projectsNational programs or projectsANR Agence Nationale de la RechercheCOPS Convective and Orographically-induced Precipitation StudyCYPRIM CYclogénèse et PRécipitations Intenses en région MéditerranéenneIRCAAM Influence Réciproque des Climats d'Afrique de l'ouest, du sud de l'Asieet du bassin MéditerranéenPERLE Programme d'Evaluation des Rejets Locaux d'EffluentsInternational programmes or projectsCERES CarboEurope Regional Experiment StrategyCIRCE Climate change and impact research : mediterranean environment (FP6)CIRENE Projet d'observation de l'océan indien tropicalENSEMBLES Ensemble-based predictions of climate changes and their impacts (FP6)EUCOS EUmetnet Composit Observing SystemEUFAR EUropean Fleet for Airborne Research (FP6)FLUXNET Programme international sur les mesures de flux de carbone dans lesécosystèmes terrestresFLYSAFE Système de vol intégré pour l'amélioration de la sécurité, la protectioncontre les imprévus, et les opérations tout tempsGEMS Global and regional Earth-system Monitoring using Satellite and in-situdata (initiative du CEPMMT)GICC Gestion et Impacts du Changement Climatique (programme du ministèrede l'écologie)GIEC Groupe Inter-gouvernemental d'Experts sur le changement Climatique(IPCC)GMES Global Monitoring for Environment and Security (Système Globald'Observation de l'Environnement pour la Sécurité, programme del'Union européenne)HIRLAM HIgh Resolution Limited Area Model (modélisation)HyMeX Hydrlogical cycle in the Mediterrannean EXperimentIMFREX IMpact sur la Fréquence des EXtrêmesIPCC Intergovernmental Panel on Climate Change (GIEC)MERSEA Marine EnviRonment and Security for the European AreaMISSTERRE Modélisation Intégrée du SyStème TERRE (projet LEFE)MOZAIC Measurement of OZone by Airbus In service airCraftMyOCEAN Successeur du projet MERSEA, visant à sa consolidation, piloté parMercator OceanPROMOTE PROtocal MOniToring for the GMES service Element for atmosphereprojectQUANTIFY QUANTIFYing the climate impact of global and european transportsystems (FP6)SAF Satellite Application FacilitySAMM Sea Atmosphere Mediterranean Model (modéle couplé régional)THORPEX THe Observing Research and Predictability EXperiment (programmemondial du GARP sous l'égide de l'OMM)TIGGE THORPEX International Grand Global EnsembleCampaignsAMMA Approche Multidisciplinaire de la Mousson AfricaineCOPS Convective and Orographically-induced Precipitation StudyAtmosphérique et de Transports d'EmissionsEGEE Volet océanographique de la campagne AMMA (golfe de Guinée)PARIS-FOG Campagne de mesures pour l'étude du cycle de vie du brouillard(Palaiseau 2006)SMOSMANIA Soil Moisture Observing System : Meteorological Automatic NetworkIntegrated ApplicationVASCO Campagne intensive d'observations atmosphériques et des échangesocéan-atmosphèreOthersADM-AEOLUS Atmospheric Dynamics Mission (satellite d'observation de la dynamiquede l'atmosphère terrestre, mis en œuvre par l'ESA)ADP Aéroports De ParisALADIN Aire Limitée, Adaptation dynamique, Développement InterNationalALADIN-Climat ALADIN-ClimatALBATROS Autoflux Linked Base for TRansfer at Ocean SurfaceAMDAR Aircraft Meteorological Data Acquisition and RelayAMSR Advanced Microwave Scanning RadiometerAMSR-E AMSR for Earth observing systemAMSU-A Advanced Microwave Sounding Unit - AAQUA Satellite du Earth observing system de la NASAAQUARIUS Satellite de mesure de la salinité de la surface de la merAR-4 Annual Report 4 (4ème rapport annuel du GIEC)ARAMIS Application RAdar à la Météorologie Infra-SynoptiqueAROME Application de la Recherche à l'Opérationnel à Méso-EchelleARPEGE Applications de la Recherche Petite Echelle Grande Echelle (modèleglobal de prévision numérique opérationnel de Météo-France)ARPEGE-Climat Modèle de simulation climatique global du CNRMARPEGE-SCM SAFRAN-CROCUS-MEPRAARGOS Advanced Research and Global Observation SatelliteASAP Automated Shipboard Aerological ProgrammeASCAT Advanced SCATterometer62 . Rapport recherche et développement 2007

ATE Analyse des Terres Émergées (SAF Eumetsat)ATOVS Advanced Tiros Operational Vertical SounderATR Avion de Transport RégionalAURA/MLS AURA (satellite)/Microwave Limb SounderBUFR Binary Universal Form for the Representation of meteorological dataCALIPSO Cloud Aerosol Lidar and Infrared Pathfinder Satellite ObservationsCAPE Convective Available Potential EnergyCARIBOU Cartographie des Analyses du RIsque de Brume et brOUillardCAROLS Cooperative Airbone Radiometer for Ocean and Land StudiesCHAMP CHAllenging Minisatellite PayloadCHIMERE Modèle de prévision de la qualité de l'air du CNRS et de l'INERISCIC Centre International de ConférencesCLOUDSAT CLOUD SATellite (satellite d'observation de la NASA)CMRS Centre Météorologique Régional SpécialiséCNRM-CM3.1 CNRM - Climate Model Version 3.1CNRM-CM3.2 CNRM - Climate Model Version 3.2CNRM/GMEI Centre National de Recherches Météorologiques/Groupe de MétéorologieExpérimentale InstrumentaleCNP Centre National de PrévisionCOBEL Code de Brouillard à l'Echelle LocaleCOSMIC Constellation Observing System for Meteorology, Ionosphere and ClimateCROCUS Modèle d'évolution du manteau neigeuxCYCOFOS Prévision pour la Méditerranée (plate-forme Chypre)DCLIM Direction de la CLIMatologieDGT Direction Générale ToulouseDIAGPACK DIAGnostic PACKageDIREN Direction InterRégionale Nord-EstDIRIC Direction InterRégionale Ile-de-france CentreDOLMEN Développement OpérationneL des Moyens d'Expertise NivologiqueDT/DSO/CMR Direction Technique/Direction des Systèmes d'Observation/Centre deMétéorologie RadarECOCLIMAP Base de données de paramètres de surfaceECUME Exchange Coefficients from Unified Multi-campaigns EstimatesEPI Evénements Précipitants IntensesEPS Ensemble Prediction SystemEQM Erreur Quadratique MoyenneERA40 Réanalyse (sur 40 ans) du CEPMMTERS European Remote Sensing satelliteERS-SCAT ERS SCATterometerEURAD EURopäisches Ausbreitungs- und DepositionsmodellFM13-SHIP Message utilisé en météorologie marineFM18-BUOY Message utilisé en météorologie marineFORMOSAT Satellite operated by Taiwan's National Space OrganizationGELATO Modèle d'évolution de la banquise développé au CNRMGLC2000 Global Land Cover 2000GMAP Groupe Météorologique d'Assimilation Prévision (CNRM)GML Geography Markup LanguageGNSS Global Navigation Satellite SystemGPS Global Positionning SystemGRACE GRAvity recovery and Climate ExperimentGRAS GNSS Reiver for Atmospheric SoundingGT1 Groupe de Travail 1 (du GIEC)GUR Groupe des Utilisateurs RadarHADISST HADley centre global sea Ice and Sea Surface TemperatureHAL Hyper Article en LigneHIRS High resolution Infrared Radiation SounderIAGOS Integration of routine Aircraft measurements into a Global ObservingSystemIASI Interféromètre Atmosphérique de Sondage InfrarougeIFS Integrated Forecasting SystemIGACO Integrated Global Atmospheric Chemistry ObservationsIOP Intensive Observation Period (IOP)IPY International Polar YearIRIDIUM Satellite en orbite polaireISBA Interaction between Soil, Biosphere and AtmosphereISBA-CC ISBA-Cycle du CarboneKFS Méthode de réduction d'entropie KFSLEANDRE2 Instrument Lidar aéroportéLEF Langue d'Eau FroideLES Large Eddy SimulationL-EPS Prévision d'ensemble sur un domaine limitéLIDAR Light Induced Detection And RangingMedSlik Modèle de dispersion de polluantsMEPRA Modèle Expert de Prévision du Risque d'AvalancheMERCATOR Projet d'océanographie opérationnelle de prévision des caractéristiquesphysiques de l'océanMESO-NH modèle numérique à MESO-échelle Non-HydrostatiqueMETOP METeorological Operationnal Polar satellitesMFS Meteorological Forecasting SystemMHS Microwave Humidity SounderMOCAGE MOdèle de Chimie Atmosphérique à Grande EchelleMODCOU MODèle hydrologique COUplé surface-souterrainMODIS MODerate resolution Imaging SpectroradiometerMOTHY Modèle Océanique de Transport d'HYdrocarburesMSG Meteosat Seconde GénérationNAO North Atlantic OscillationNH Non HydrostatiqueNIVOSE Station automatique de mesure en haute montagneOD3D Modèle de météorologie marineOPA Océan PAralléliséOPAMED Océan Parallélisé/MEDiterranéeORCHIDEE ORganizing Carbon and Hydrology In Dynamic EcosystEmsOSSE Observing System Simulation ExperimentsOTICE Organisation du Traité d'Interdiction Complète des Essais nucléairesPALM Projet d'Assimilation par Logiciel Multi-méthodesPANTHERE Programme Aramis Nouvelles Technologies HydrométéorologieExtension et REnouvellementPCRD Programme Cadre de Recherche et DéveloppementPEARP Prévision d'Ensemble ARPègePrév'Air Simulations déterministes de la qualité de l'air en France et en EuropeRADOME Réseau d'Acquisition de Données et d'Observations MétéorologiquesÉtenduRALI Système RAdar-LIdarRASTA Radar Aéroporté et Sol de Télédétection AtmosphériqueROC Relative Operating CharacteristicsSAFRAN Système d'Analyse Fournissant des Renseignements Atmosphériquesà la NeigeSAF-NWC Satellite Application Facility - NoWCastingSBD Short Burst Data (bouées)SIGMA Système d'Identification du Givrage en Météorologie AéronautiqueSIM Safran-Isba-ModcouSIR Safran-prévision/Isba-RouteSMOS Soil Moisture and Ocean SalinitySMT Système Mondial de TransmissionSOP Special Observation PeriodSST Sea Surface TemperatureSURFEX SURFace EXternaliséeSVP-B Surface Velocity Program (océanographie)SYMPHONIE Modèle 3D aux équations primitives développé par le Laboratoired'AérologieTRIP Total Runoff Integrating PathwayTSM Température de Surface de la MerUHF Ultra High FrequencyUTC Universal Time Coordonnated (TU)VEGETATIONB Module du satellite SPOTVHF Very High FrequencyWIMS-Cb Weather InforMation Systems on Cumulonimbus3D-Var Assimilation variationnelle tridimensionnelle4D-Var Assimilation variationnelle quadridimensionnelle63 . Rapport recherche et développement 2007

Management structureNational meteorological researchs centreHead : Éric BrunDeputy Head - Toulouse : Joël PoitevinScientific Dep. Head - Toulouse : Jean PailleuxDeputy Head - Paris : Pascale DelécluseGENERAL SERVICESParis & ToulouseMETEOROLOGICAL AVIATION CENTRECentre head : Marc PontaudCAM - ToulouseSNOW RESEARCH CENTRECentre head : Pierre EtcheversCEN - GrenobleMARINE METEOROLOGY CENTRECentre head : Jean RollandCMM - BrestMODELLING FOR ASSIMILATION AND FORECASTING GROUPGroup head : François BouttierGMAP - ToulouseEXPERIMENTAL AND INSTRUMENTAL METEOROLOGY GROUPGroup head : Jean-Louis BrenguierGMEI - ToulouseCLIMATE AND LARGE SCALE MODELLING GROUPGroup head : Serge PlantonGMGEC - ToulouseMESO-SCALE MODELLING GROUPGroup head : Joël NoilhanGMME - ToulouseSTUDIES DANS INTERNAL KNOWLEDGE TRANSFERS GROUPGroup head : Christine DrevetonRETIC - Toulouse64 . Research and development: annual report 2007

Centre national de recherches météorologiques42, avenue Gaspard-Coriolis 31057 Toulouse Cedex 1 France - Tél. : (33) 5 61 07 93 70 - Fax : (33) 5 61 07 96 00http: //www.cnrm.meteo.fr - Mail : contact@cnrm.meteo.frEdition Météo-FranceDirection commerciale et de la communication.Imprimé sur du papier écologique, sur les presses de l’imprimerie de Météo-France D2C/IMP, labelisée Impri’vert ® .Conception, réalisation et impression D2C/IMP TrappesMaquette de couverture www.eurorscg.fr

Researchanddevelopment:annual report2007© Yann Arthus-Bertrand/Altitude - www.yannarthusbertrand.org – www.goodplanet.org • Edition août 2008Météo-France1, quai Branly75340 Paris Cedex 7FranceTel.: +33 1 45 56 71 71Fax: +33 1 45 56 71 11www.meteofrance.comMétéo-France is certifiedISO 9001-2000 by BVQI© Météo-France 2008Dépôt légal août 2008ISSN 1166-732 X

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