2012 AGU Chapman Conference on Remote Sensing of the ...

Vila, Daniel A.Satellite Rainfall Retrieval Assessment overDifferent Rainfall Regimes and the ‘Chuva’Experiment Preliminary ResultsVila, Daniel A. 1, 2 ; Machado, Luiz A. 1 ; Lima, Wagner 11. DSA/CPTEC/INPE, Cachoeira Paulista, Brazil2. CICS, ESSIC/UMD, College Park, MD, USAThe first part of this paper evaluates different satellitebasedmethodologies for precipitation retrieval over differentrainfall regimes in the Brazilian territory along the year onseasonal basis. The algorithms analyzed in this study are:Hydroestimator, 3B42RT and CMORPH. The evaluation ofthese algorithms was performed by comparing against dailyrain gauges. Preliminary results showed a deficiency inestimating precipitation in northeastern Brazil due to thepresence of low warm-top precipitating clouds (warmclouds). In order to address some of those issues, one of theobjectives of the “Cloud processes of tHe main precipitationsystems in Brazil:A contribUtion to cloud resolVingmodeling and to the GPM (GlobAl PrecipitationMeasurement) “ CHUVA experiment is to evaluate andvalidate the performance of satellite rainfall algorithms inestimating rainfall produced by different rainfall regimesand precipitating systems. Preliminary results of the firstfield campaigns will be presented for discussion.Walker, AnneAirborne and Ground-Based Passive MicrowaveRadiometer Field Campaigns for the Developmentand Validation of new Satellite Derived SnowDatasetsDerksen, Christopher 1 ; Walker, Anne 1 ; Pulliainen, Jouni 2 ;Lemmetyinen, Juha 2 ; Luojus, Kari 21. Environment Canada, Climate Research Division,Toronto, ON, Canada2. Arctic Research Center, Finnish Meteorological Institute,Helsinki, FinlandA series of field campaigns with airborne and groundbasedmicrowave radiometers were conducted acrosssub-Arctic Canada, to address the development andevaluation of new satellite derived snow water equivalent(SWE) datasets. Campaign activities were focused on twoareas: (1) In 2008, airborne and satellite brightnesstemperature (TB) measurements were combined withintensive field observations of snow cover at three sitesacross the Canadian sub-Arctic to develop a new tundraspecificpassive microwave snow water equivalent (SWE)retrieval algorithm specific to high latitude environments.This complements the existing suite of mid-latitude landcover specific algorithms developed and utilized atEnvironment Canada. (2) Plot-scale TB measurements wereacquired in forest, open, and lake environments nearChurchill, Manitoba, Canada with mobile sled-basedmicrowave radiometers during the 2009/10 winter season.These measurements were combined with coincidentphysical snow measurements to evaluate multi-scale forwardTB simulations with the Helsinki University of Technologysnow emission model, a fundamental component of a newnorthern hemisphere SWE dataset recently produced by theEuropean Space Agency GlobSnow initiative(www.globsnow.info), through an assimilation of satellitepassive microwave data and snow depth measurements fromsynoptic weather stations. This presentation will provide anoverview of the measurements made in these campaigns, anda synthesis of snow emission model simulations and SWEretrieval experiments. In general, results indicate thataddressing sub-grid heterogeneity remains a key challenge inthe development of satellite retrieval algorithms becausevariable land cover and associated physical snow propertiesdrive uncertainty in the forward TB simulations and withinthe SWE retrieval schemes. Furthermore, satellite-scalepassive microwave SWE retrievals can provide only a singlevalue for coarse resolution grid cells, which introduces animplicit level of uncertainty for nearly all applications. Thesecampaigns also contributed to preparatory activities for theCold Regions High Resolution Hydrological Observatory(CoReH2O), a dual frequency SAR mission dedicated toobservations of the cryosphere (CoReH20 is one of thecandidates for the European Space Agency’s next satellite inthe series of Earth Explorer Core missions). These proposedspaceborne Ku- and X-band SAR measurements, includingpotential synergistic use with satellite microwaveobservations, will represent considerable improvement inspatial resolution.Walker, AnneSpring thaw detection from satellite active andpassive microwave measurementsWang, Libo 1 ; Walker, Anne 1 ; Derksen, Chris 11. Climate Research Division, Environment Canada,Toronto, ON, CanadaThe timing of seasonal transition from frozen to nonfrozenconditions is coincident with the seasonal switchfrom the landscape being a net source to a net sink foratmospheric carbon. It also affects the length of the growingseason and the surface water and energy balances. Bothsatellite active and passive microwave sensors have beenwidely used to monitor landscape freeze/thaw status. In thisstudy, we investigate the capability of combined enhancedresolution active/passive microwave data from the SeaWindsscatterometer onboard QuikSCAT and the AdvancedMicrowave Scanning Radiometer for the Earth ObservingSystem (AMSR-E) for spring thaw detection. An attempt ismade to differentiate the timing of spring snowmelt onsetand soil thaw, which are not resolved from previous methodsusing the original resolution satellite data. In situobservations of snow depth and soil temperature dataobtained from Boreal Ecosystem Research and MonitoringSites (BERMS) locations in the southern boreal forest ofSaskatchewan and measurements from International PolarYear campaigns in northern Quebec (tundra) were used toassist in the interpretation of the satellite measurements.147