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WRF Model: Physics Implementation. Shu-hua Chen. OUTLINE. Physics schemes Three_level Structure Rules for WRF physics WRF Physics Features WRF Language What you might need to do. P. F. I. H. R. C. Y. W. S. S. Physics Schemes.
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WRF Model: Physics Implementation Shu-hua Chen OUTLINE Physics schemes Three_level Structure Rules for WRF physics WRF Physics Features WRF Language What you might need to do
P F I H R C Y W S S Physics Schemes Physical Process Available Microphysics Kessler, Lin et al. , Ncloud3, Nloud5 Cumulus KF, BMJ Subgrid scale turbulence TKE, Smagrinsky, Constant K Radiation RRTM(L), Dudhia(S), Goddard(S) PBL MRF Surface layer Similarity theory Land-surface layer 5-layer soil temperature
P F I H R C Y W S S • User friendly • Different dynamics cores • Simple Three-level structure => Physics Interface Design
P F I H R C Y W S S Solver Physics_driver SELECT CASE (CHOICE) CASE ( NOPHY ) CASE( SCHEME1 ) CALL XXX CASE( SCHEME2 ) CALL YYY . CASE DEFAULT END SELECT Individual physics scheme ( XXX ) Three-level Structure
P F I R H C W Y S S phy_prep phy_init Radiation_driver pbl_driver Cumulus_driver moist_physics_prep microphysics_driver … INIT . WRF solve_rk … ADV TENDENCIES . ADVANCE VARS .
P F I H R C Y W S S phy_prep & moist_physics_prep • Decouple variables • Convert variables from C grid to A grid
P F I H R C Y W S S Three Sets of Dimensions Domain size: ids, ide, jds, jde, kds, kde Memory size: ims, ime, jms, jme, kms, kme Tile size: its, ite, jts, jte, kts, kte
P F I H R C Y W S S halo tile tile tile halo halo (its,ite) tile tile tile halo (ims,ime) Tile size (its,kts,jds)
P F I H R C Y W S S Rules for WRF Physics • Coding rules • One scheme one module • Naming rules • Vectorized code preferred ( might depend on which physics component )
P F I H R C Y W S S Coding Rules 1. F90 • Replace continuation characters in the 6th column with f90 continuation `&‘ at end of previous line b)Replace the 1st column `C` for comment with `!` 2. No common block 3. Use “ implicit none ” 4. Use “ intent ” 5. Variable dimensions and do loops
P F I H R C Y W S S Naming Rules module_yy_xxx.F(module) yy = ra is for radiation bl is for PBL cu is for cumulus mp is for microphysics. xxx = individual scheme ex, module_cu_kf.F
P F I H R C Y W S S Naming Rules RXXYYTEN(tendencies) XX = variable (th, u, v, qv, qc, … ) YY = ra is for radiation bl is for PBL cu is for cumulus ex, RTHBLTEN
P F I H R C Y W S S WRF Physics Features • Unified global constatnts (module_model_constants.F) • Unified some calculations (saturation mixing ratio) • Vertical index (kms is at bottom) • kme = kte + 1 (physics) kme = kte (dynamics)
P F I H R C Y W S S WRF Language • Patch, tile, …. • Moisture field, moist(i,k,j,?), is 4D • P_QV, P_QC, P_QR, P_QI,P_QS, P_QG (module_state_description.F) • PARAM_FIRST_SCALAR IF ( P_QI .ge. PARAM_FIRST_SCALAR ) . . .
P F I H R C Y W S S mp_physics = 2, ra_lw_physics = 1, ra_sw_physics = 1, bl_sfclay_physics = 1, bl_surface_physics = 1, bl_pbl_physics = 1, cu_physics = 1, namelist.input