Examples of atmospheric modeling II

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Examples of atmospheric modeling II

(NASA Earth Observatory, 2005)


Tracks and Intensity of Tropical Storms(150 years, until 2006)Atmospheric modelling - Examples - Tropical Storms(NASA Earth Observatory)


Detection of tropical storms inatmosphere modelsrelative vorticity at850 hPa> 3.5*10 -5 s -1vertical temp.structureT ano(300 hPa) >T ano(850 hPa)wind speedminimum at 10 m> 15 m/svertical structureof wind fieldaround stormcenter|V 850| > |V 300|min. surfacepressurewithin 7x7 gridpoints aroundpoint fulfillingvorticitycriterionminimumduration of event≥ 1.5 daystropospherictemp. anomaly(700, 500, 300hPa)> 3°C within7x7 grid pointareaAtmospheric modelling - Examples - Tropical Storms(criteria accord. to Bengtsson et al., 1996)


Simulation of tropical stormsECHAM4/T106-AMIP-Simulation 1979-1998DJFJJA(Merkel, 2003)Atmospheric modelling - Examples - Tropical Storms


ENSO and tropical stormsAtmospheric modelling - Examples - Tropical Storms(Pielke and Landsea, 1999)


ENSO and tropical stormsECHAM4 simulation with AMIP SST 1979-1999(Merkel, 2003)Atmospheric modelling - Examples - Tropical Storms


Which role does the sea surfacetemperature in a specific oceanbasin play?• Observations can only show result of signalsuperposition• Which ocean basin is most important for weatherand climate in a certain region?• AGCM experimental setup:SST anomalies in region of interest prescribed,fixed/climatological SST elsewhere=> investigate impact on the atmosphereAtmospheric modelling - Examples - Relative roles of ocean basins


West African PrecipitationAnomalies ofJune-Sept. precipitation[mm][year][year](Fink, 2006)Atmospheric modelling - Examples - Relative roles of ocean basins


Impact of Indian Ocean SST on WestAfrican rainfallECHAM4.5 simulation with AMIP SSTSST anomaly experiments to examine role of Indian Ocean SSTin inducing West African droughts(Bader, 2005)Atmospheric modelling - Examples - Relative roles of ocean basins


Impact of Atlantic and Indian OceanSST on West African rainfallECHAM4.5 simulation with AMIP SSTSST anomaly experiments to examine role of Atlantic and Indian OceanSST in inducing West African droughts(Bader, 2005)Atmospheric modelling - Examples - Relative roles of ocean basins


West African precipitation responseto East Atlantic SST anomaliesECHAM4.5 simulation with AMIP SSTEast Atlantic SST + 1KEast Atlantic SST - 1K[mm/mon](Bader, 2005)Atmospheric modelling - Examples - Relative roles of ocean basins


Typical El Niño patternRegression [K/K] of global observed DJF SST ontoDJF Niño3 timeseries (Reynolds dataset)Atmospheric modelling - Examples - Relative roles of ocean basins


Global vs. tropical Pacific-only SSTAECHAM4 simulations: Sea level pressure response [hPa]Global SST anomaliesTropical Pacific SST anomalies only(Merkel, 2003)Atmospheric modelling - Examples - Relative roles of ocean basins


Examples for atmospheric modellingFocus on- present climate• Atmospheric Modelling Intercomparison Project• ENSO teleconnections• West African precipitation- future climate• high resolution experiment as an extension ofcoupled model run- past climate (Last Glacial Maximum)


Future Climate Scenarios: MPI-ModelPreindustrial controlGreenhouse gasesGreenhouse gases + aerosolsObservationsGlobal and annual mean temp. anom. [°C]ECHAM4-OPYC runs for IPCC TAR,Fig. adapted from Rockner, 2004Atmospheric modelling - Examples - Future Climate Scenarios


Future Climate Scenariostimeslices withAGCM model athigh resolutionSST, sea ice,..presentclimate(1980-2000)SST, sea ice,..futureclimate(2080-2100)baseline simulationwith AO model atcoarse resolutionAtmospheric modelling - Examples - Future Climate Scenarios


Examples for atmospheric modellingFocus on- present climate• Atmospheric Modelling Intercomparison Project• ENSO teleconnections• West African precipitation- future climate• high resolution experiment as an extension ofcoupled model run- past climate (Last Glacial Maximum)


Paleo climate simulations: LastGlacial Maximum (21.000 yr BP)Orbital parametersSource: Scott Rutherford Source: Montana State Univ.Continental ice sheetsand albedoCoupled oce.-atm.general circulationmodelGreenhouse gasconcentrationsCH 4CO 2 N 2 OSea level changesSource: SOEST, HawaiiAtmospheric modelling - Examples - Paleo Climate


Paleo climate simulations (LGM)Ice sheet distribution at 0 ky BPColour: Topographic heights in mIce sheet distribution at 21 ky BPColour: Topographic heights in m(Data: Peltier, 2005)Atmospheric modelling - Examples - Paleo Climate


Paleo climate simulations (LGM)Seasonal mean (DJF) zonal wind changes [m/s]in the upper troposphere (200 hPa)Atmospheric modelling - Examples - Paleo Climate


Paleo climate simulations (LGM)Seasonal mean (DJF) mid-tropospheric (500 hPa) wind fieldControlLGMAtmospheric modelling - Examples - Paleo Climate


Paleo climate simulations: The PaleoModelling Intercomparison Project(PMIP)Annual mean surface air temperature anomaly [°C]at the Last Glacial Maximum (21.000 yr BP)tas LGM - CTRL NH annual mean0PMIP2 PMIP2 Coupled OA PMIP1 PMIP1 SSTfixed PMIP1 PMIP1 SSTcslab-1-2-3-4°C-5-6-7-8-9-10(Braconnot et al., 2007)Atmospheric modelling - Examples - Paleo Climate


Outlook● Atmosphere-only models get more and more complex- increasing resolution- inclusion of more processes- stochastic parameterization of processes- atmospheric chemistry● More complex coupling strategies⇒ interactions with land biosphere/vegetation⇒ fully dynamic stratosphere (vertical wave propagation,tropospheric circulation governed by stratosphere)⇒ coupling to fully complex ocean models (eddy resolving)⇒ coupling to continental ice sheet modelsExample: PMIP1: A-onlyPMIP2: AO, AOV setups for paleo climateAtmospheric modelling - Summary and Outlook


OutlookIce sheetIce sheetCarbon cycle, biogeochemistry(Liu and Alexander, 2007)Atmospheric modelling - Summary and Outlook


Thank you for your attention„N’estimez l’argent ni plus ni moins qu’il ne vaut: c’estun bon serviteur et un mauvais maître.“(Alexandre Dumas Fils)...How about models?...Model resultsObservational and paleo dataAtmospheric modelling - Summary and Outlook

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