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The externalized surface

The externalized surface. Sea and ocean. Lakes. Vegetation and soil. Town. Summary. organisation at M-F Interest of an externalized surface Description of SURFEX The implicit couplling On-going an future work at M-F HIRLAM<>ALADIN. Some presentations ….

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The externalized surface

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  1. The externalized surface Sea and ocean Lakes Vegetation and soil Town

  2. Summary • organisation at M-F • Interest of an externalized surface • Description of SURFEX • The implicit couplling • On-going an future work at M-F • HIRLAM<>ALADIN

  3. Some presentations … • CNRM (Centre national de recherches météorologiques) • GMAP (NWP) F. Bouttier • PROC (physical processes) F. Bouyssel, E. Bazile… • COOPE (scientific cooperation) D. Giard, C. Fisher, … • ALGO (algorithms) R. El Khatib, … • … • GMME (medium scale meteorology) J. Noilhan • MC2 (surface /hydrology /carbon fluxes) P. Le Moigne, E. Martin • Meso-NH (C. Lac, S. Malardel) • TURBAU (turbulence/fog/town) V. Masson • … • GMGEC (climate group) • UDC (dynamic of the climate) H. Douville • EAC (Arpege/Climat) P. Marquet • … • CEN (snow group – avalanches) AROME : A project (F. Bouttier, G. Hello), staff from GMAP/GMME

  4. Objectives Separate the surface schemes from the atmospheric model - difficulties for the comparison of surface model, - increased complexity of surface and atmospheric code - allows to use the same surface code for several atmospheric models or the reverse (NWP, research, climate models, off-line runs) Simulate Exchanges between surface and atmosphere(momentum, heat, water, CO2, chemical species) Litterature : Polcher et al, 1998 : A proposal for for a general interface betweeen land-surface schemes and general circulation models, Global Planetary change, 19, 263-278. Best et al, 2004 : A proposed structure for coupling tiled surfaces with the planetary boundary layer, J. of Hydrometeor.,5, 1271-1278.

  5. The externalized surface • 4 surface types : the tiles Town Lake ATMOSPHERE SURFACE Nature Town Sea Lake Nature Sea

  6. SURFACE Lake Town Sea Nature ... 1: sol nu 2: rochers 3: neige permanente 4: décidus 5: conifères 6: feuillus 7: cultures en C3 8: cultures en C4 9: cultures irriguées 10: pâturages 11: zones herbeuses tropicales 12: parcs et jardins The Nature surface is divided in patches

  7. The physical schemes Sea and ocean : prescribed SST, Charnock formula Lakes : prescribed temperature, Charnock formula Vegetation and soil : ISBA (Interface Soil Biosphere Atmosphere) Town : TEB (Town Energy Balance)

  8. Physics ISBA: Soil options: Force restore, 2 layers , temp, water, ice Force restore, 3 layers , temp, water, ice Diffusion, N layers , temp, water, ice Vegetation options: Noilhan and Planton 89 (~Jarvis) AGS (photsynthesis and CO2 exchanges) AGS and interactive vegetation Hydrology options: no subgrid process subgrid runoff, subgrid drainage Snow options: Douville 95 (1 layer, varying albedo, varying density) Operational (Bazile, Giard) Boone and Etchevers 2000 (3 layers, albedo, density, liquid water in snow pack) TEB: Canyon approach: detailed radiation scheme (trapping – shadow effect) heat storage in buildings

  9. The externalized surface algorithm Initialization of Physiographic fields ECOCLIMAP, FAO GTOPO30 Initialization of Variables fields From several models, Prescribed fields Run • 2m T and H, 10m wind, energy budget, water budgets, physiographic fields from ecoclimap • For : • the whole surface (aggregated diagnostics) • each type of surface (sea, lakes, vegetation, town) each patch in case of several patches in ISBA Diagnostics

  10. How to use the same code in different universes? • File types (MESO-Nh, netcdf, Ascii, ALADIN (soon)) • - All reading (writing) orders from the surface are given by the same routine • This routine, READ_SURF, chooses the correct reading routine: • READ_SURF (file type, field) READ_SURF for Arome file (field) READ_SURF for MesoNH file (field) READ_SURF for netcdf file (field) READ_SURF for Ascii file (field)

  11. Run Before first time step During run, at each timestep Output files Type of input file Sun position Radiative fluxes Sun position Atm. Forcing Rain, snow fall Albedo, Emissivity, radiative temp. Albedo, Emissivity, radiative temp. Momentum fluxes Heat flux Water vapor flux CO2 flux Chemical fluxes Type of output file Atmospheric model Surface writing Surface run Surface Initialisation surface

  12. What to do for the externalization • Surface variables /atmospheric variable : if a physical parametrisation needs a surface variable, you need to ask the surface • In the run several mode for the surface : • Enquiry : for radiation (alb, skt, emis.), or use of pseudo historical variable • Diagnostic : return fluxes (for calculation of diffusion coefficients • Time-stepping : all (+temp. advance) • Time stepping is implicit (mandatory for long time step) or explicit • Separation of all other parts (initialisation, diagnostic, I/O) • Development of more complete enquiry mode for analysis (soil moisture, …) not described in Best paper

  13. Implicit coupling with the atmosphere 1 Vertical diffusion Downward sweep Lower atmospheric level N Surface Ts + Fluxes on each tiles, Average fluxes Upward sweep Implicit coupling possible for ISBA D95

  14. Exchanges of data (arg. of coupling_surf_atm) HCOUPLING ! type of coupling, 'E' : explicit,'I' : implicit KYEAR ! current year (UTC) KMONTH ! current month (UTC) KDAY ! current day (UTC) PTIME ! current time since midnight (UTC, s) KI ! number of points KSV ! number of scalars KSW ! number of short-wave spectral bands PTSUN ! solar time (s from midnight) PTSTEP ! atmospheric time-step (s) PZREF ! height of T,q forcing (m) PUREF ! height of wind forcing (m) ! PTA ! air temperature forcing (K) PQA ! air humidity forcing (kg/m3) PRHOA ! air density (kg/m3) PSV ! scalar variables(chemistry:first char. in HSV:'#'(molecule/m3)) ! ! HSV ! name of all scalar variables PU ! zonal wind (m/s) PV ! meridian wind (m/s) PDIR_SW ! direct solar radiation (on horizontal surf.) (W/m2) PSCA_SW ! diffuse solar radiation (on horizontal surf.) (W/m2) PSW_BANDS ! mean wavelength of each shortwave band (m) PZENITH ! zenithal angle (radian from the vertical) PAZIM ! azimuthal angle (radian from North, clockwise) PLW ! longwave radiation (on horizontal surf.) (W/m2) PPS ! pressure at atmospheric model surface (Pa) PPA ! pressure at forcing level (Pa) PZS ! atmospheric model orography (m) PCO2 ! CO2 concentration in the air (kg/m3) PSNOW ! snow precipitation (kg/m2/s) PRAIN ! liquid precipitation (kg/m2/s) ! PSFTH ! flux of heat (W/m2) PSFTQ ! flux of water vapor (kg/m2/s) PSFU ! zonal momentum flux (Pa) PSFV ! meridian momentum flux (Pa) PSFCO2 ! flux of CO2 (kg/m2/s) PSFTS ! flux of scalar var. (kg/m2/s) ! PTRAD ! radiative temperature (K) PDIR_ALB! direct albedo for each spectral band (-) PSCA_ALB! diffuse albedo for each spectral band (-) PEMIS ! emissivity (-) ! PPEW_A_COEF, PPEW_B_COEF, PPET_A_COEF, PPEQ_A_COEF, PPET_B_COEF, PPEQ_B_COEF • Input Sun position, Radiative forcing, Met forcing, rain, snow, date, etc… • As and Bs • Outputs • Albedo, • Emissivity, • radiative temp. • Momentum fluxes • Heat flux • Water vapor flux • CO2 flux • Chemical fluxes • In case of explicit coupling, A=0, B=T,q,u,v

  15. Main changes ARPEGE/ALADIN Init. : MASTER > SUINIT > … > SUNIT_SX > … > STEPO Run (APLPAR) • Before : • the ISBA subroutines are called by APLPAR • The new surface temperature is solved inside the vertical diffusion routine (ACDIFUS) • After : • ACDIFUS is splitted : ACDIFV1, ACDIFV2, • SURFEX is called between the 2 • ARPEGE/ALADIN : ACSURFEX > coupling_sur_atm • Meso-Nh GROUNDF > coupling_sur_atm • Use of pseudo historical variables (for the moment)

  16. Present situation and short term plans for ALADIN • SURFEX is developed and used in Meso-NH and the AROME prototype (early 2005), explicit mode • Test of implicit coupling within the 1D ARPEGE code (almost finished) • Phasing the modifications of ARPEGE (APLPAR+ init+diag) (begins in october 2005 ?) finalize all interface points + some other points (e.g. antifibrilation) • Develop I/O for ARP/ALADIN files • Develop I/O in parallel computation (loop NPROMA) • development of the « enquiry mode » (run(?) and assimilation)(temporary solution : keep the same coefficient for turb. fluxes formulation in surfex than in the old version). • Many « little » work to do to insure conversion from old version to SURFEX / Much more for assimilation • To be tested in ALADIN mid 2006.

  17. HIRLAM <> ALADIN • Agreement on the Best interface.Write a detailed paper on the several mode of surface call • Run : more or less OK • Enquiry, diagnostic, to be discussed (not yet discussed for us), also for the assimilation mode. • First objective : have the same interface for SURFEX and HIRLAM externalized surface (not necessary to have an implicit coupling coded, limitation for long time step?) • Further points : see paper ...

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