COSMO/ICON land-surface processes and physiographic data. J. Helmert with contributions from colleagues infe1

Transcription

1 COSMO/ICON land-surface processes and physiographic data J. Helmert with contributions from colleagues infe1 GB FE 14 03/2017

2 Physics in ICON Process Authors Scheme Origin Radiation Non-orographic gravity wave drag Sub-grid scale orographic drag Cloud cover Microphysics Convection Turbulent transfer Land Mlawer et al. (1997) Barker et al. (2002) RRTM (later with McICA & McSI) ECHAM6/IFS Ritter and Geleyn (1992) δ two-stream GME/COSMO Scinocca (2003) Orr, Bechtold et al. (2010) wave dissipation at critical level Lott and Miller (1997) blocking, GWD IFS Doms and Schättler (2004) sub-grid diagnostic GME/COSMO Köhler et al. (new development) diagnostic (later prognostic) PDF ICON Doms and Schättler (2004) Seiffert (2010) prognostic: water vapor, cloud water, cloud ice, rain and snow IFS GME/COSMO Bechthold et al. (2008) mass-flux shallow and deep IFS Plant, Craig (2008) stochastic based on Kain-Fritsch LMU, Munich Raschendorfer (2001) prognostic TKE COSMO Mironov, Machulskaya (new) prognostic TKE and scalar var. ECHAM6 Neggers, Köhler, Beljaars (2010) EDMF-DUALM IFS Heise and Schrodin (2002), Helmert, Mironov (2008, lake) tiled TERRA + FLAKE + multi-layer snow GME/COSMO Raddatz, Knorr, Schnur JSBACH ECHAM6

3 Key task for parametrization Parametrization schemes express the effect of subgrid/subscale processes on resolved variables solving the closure problem Radiative transfer Transfer of heat, moisture and momentum Land/Sea surface characteristics courtesy to Anton Beljaars

4 Key task for parametrization Parametrization schemes express the effect of subgrid/subscale processes on resolved variables solving the closure problem Radiative transfer Cloud Physics Transfer Scheme Radiation Transfer of heat, moisture and momentum Data Assimilation Land-Surface Scheme TERRA Land/Sea surface characteristics ExtPar Physiographic data courtesy to Anton Beljaars

5 Parametrization schemes Land-Surface Scheme TERRA Consider surface energy budget Impact parameters: soil moisture and type, vegetation, surface roughness and land-use class, snow coverage Surface temperature depends on surface energy budget determines PBL development Relationship between energy budget and water budget has to be considered courtesy to Anton Beljaars

6 Parametrization schemes Land-Surface Scheme TERRA Surface temperature considers temperature of snow covered and snow free surface fraction (snow tiles) One-layer vegetation Evapotranspiration after Dickinson (1984) interception reservoir Urban areas: modified surface roughness, leaf area index, plant coverage - detailed consideration possible Transfer of heat, moisture and momentum PBL coupling: application of the turbulence scheme at the lower model boundary and iterative interpolation Consideration of TILES (in ICON) courtesy to Anton Beljaars

7 Parametrization schemes Land-Surface Scheme TERRA Snow: One layer prognostic variables : snow temperature, snow water equivalent, snow density, snow albedo - Multi-layer snow model possible Soil: 7-layer soil model + 1 climate layer - layer-depth between 1 cm and m Consider heat transfer and water transport including soil type dependent computation of fractional freezing/melting of total soil water content in 6 active soil layers in Transfer the soil of including heat, moisture soil ice and momentum Ocean: Prescribed surface temperature (analysis) - Charnock formulation for roughness length Sea ice model Fresh water lakes: Lake model courtesy to Anton Beljaars

8 ICON dynamics-physics cycling Dynamics dtime Tendencies Tracer Advection dtime * iadv_rcf Fast Physics Satur. Adjustment Land/Lake/Sea-Ice Turbulent Diffusion Microphysics Satur. Adjustment Slow Physics Convection Cloud Cover Radiation Non-Orographic Gravity Wave Drag Sub-Grid-Scale Orographic Drag dt_conv dt_conv dt_rad dt_gwd dt_sso Output dt_output

9 ICON setup for land-surface Current experiments for new COSMO version NAMELIST LND_NML LMELT T LMELT_VAR T ITYPE_HEATCOND 3 IDIAG_SNOWFRAC 20 ITYPE_EVSL 4 ITYPE_ROOT 2 ITYPE_INTERCEPTION 1 CWIMAX_ML 5,00E-04 ITYPE_HYDBOUND 1 LSTOMATA T LSEAICE T LLAKE T

10 TERRA - Structure H 1 L v E 1 H 2 L v E 2 H 3 L v E 3 H 4 L v E 4 H 5 L v E 5 H 6 L v E

11 TERRA Energy budget Solar radiation Sensible heat Latent heat Snow Heat release by freezing/melting Snow/Soil Heat exchange Heat release by freezing/melting Soil heat flux.

12 TERRA Energy budget Thermal processes Evolution of the soil temperature Evolution of the soil temperature layer 1 Surface forcing

13 Frozen soil - Soils maintain some liquid water at temperatures below freezing point - Freezing point depression: Curvature of water around small hydrophilic soil particles (Davis, 2001) - - Analogous to freezing point depression by solutes in water - Result: Thin liquid water films surrounding soil particles at T<0 C

14 Frozen soil For peat f_c and f_s of sand is used

15 Frozen soil

16 Snow Main effects Insulation effect: Decoupling of soil from atmosphere (30%-90% of the snow mantle is air) Albedo Effect: Higher albedo than any other natural surface ( for bare ground/low vegetation, for snow in forests) Snow melting prevents rise of surface temperature above 0 C for a long period in spring impact on hydrological cycle and energy budget at surface Snow Model One layer prognostic variables : snow temperature, snow water equivalent, snow density, snow albedo G. Balsamo, 2007 Multi-layer Vertical profiles in snow pack; considers equations for the snow albedo, snow temperature, density, total water content and content of liquid water. Therefore phase transitions in the snow pack are included.

17 Snow aging processes Albedo and density High Albedo Low Density Low Albedo High Density

18 Snow Q rad T snow f ( 1 f ) snow snow T s h s ρ s, SWE T s T so1

19 Snow Snow fraction Schneebedeckungsgrad Schneebedeckungsgrad ist lineare Funktion des SWE SWE f snow = m Einfluss von Wald und subskaliger Orographie wird im Schneebedeckungsgrad nicht berücksichtigt f snow = f ( h, SSO, landuse, freshsnow) snow Existenz von Schnee wird bisher bei der Bestimmung der skalaren Rauigkeitslänge nicht berücksichtigt Roesch et al., 2001

20 Snow Thermal processes for snow Evolution of the snow temperature Heatflux through the snow Surface forcing

21 ICON setup for land-surface Current experiments for new COSMO version NAMELIST LND_NML LMELT T LMELT_VAR T ITYPE_HEATCOND 3 IDIAG_SNOWFRAC 20 ITYPE_EVSL 4 ITYPE_ROOT 2 ITYPE_INTERCEPTION 1 CWIMAX_ML 5,00E-04 ITYPE_HYDBOUND 1 LSTOMATA T LSEAICE T LLAKE T

22 TERRA Water budget Transpiration Evaporation Snow, Rime Rain, Dew Snow Interception Surface runoff Infiltration Capillary transport Gravitational transport Sub-Surface runoff.

23 TERRA - Structure Hydrological processes

24 TERRA - Structure Hydrological processes Interception store Snow store Soil water Soil ice

25 TERRA Evapotranspiration (Ament, 2006)

26 TERRA Soil water transport Evolution of the soil liquid water fraction Richards equation for the water flux Hydraulic diffusivity and conductivity are soil type dependent

27 ICON setup for land-surface Current experiments for new COSMO version NAMELIST LND_NML LMELT T LMELT_VAR T ITYPE_HEATCOND 3 IDIAG_SNOWFRAC 20 ITYPE_EVSL 4 ITYPE_ROOT 2 ITYPE_INTERCEPTION 1 CWIMAX_ML 5,00E-04 ITYPE_HYDBOUND 1 LSTOMATA T LSEAICE T LLAKE T

28 Physiographic data NWP and Climate models: e.g. ICON R02B07 13 km, CDE 2.5 km Orography GLOBE: 1 km ASTER: 0.03 km ExtPar Physiographic data B. Ritter Aerosols: 500 km NDVI: 5 km Soil data DSMW: 10 km HWSD: 1 km Lake: 1 km Surface albedo: 5 km T2M climatology: 50/500 km Land use GLC km GLCC 1 km GlobCover 0.3 km Physiographic data on model grid

29 Impact of physiographic data LE H H LE

30 Uncertainties: Land-Sea Mask GLCC USGS land use / land cover system GLC2000 land use classes Globcover 2009 (now used to derive land-sea mask)

31 GLOBE Orography: HSURF

32 Land use: LAI_MAX

33 Land use: Evergreen Forest

34 Land use: Surface Emissivity

35 Albedo-MODIS: ALB_DIFF CLIM

36 Soil-DMSW: Soil Type

37 COSMO/ICON land-surface processes and physiographic data Very efficient land-surface scheme TERRA Considers snow, vegetation, frozen soil Energy and water budget Valid for all Earth s climatic zones Uses physiographic data from EXTPAR GB FE 14 03/2017