WRF Physics Options Jimy Dudhia
Dec 17, 2015
diff_opt=2
2nd order horizontal diffusionAllows for terrain-following coordinateUses km_opt 1: constant (khdif and kvdif used) 2: 1.5-order TKE prediction 3: Smagorinsky (deformation/stability
based K)
damp_opt=1
Upper level damping layerEnhanced horizontal and vertical diffusion at topCosine function of heightUses additional parameters zdamp: depth of damping layer dampcoef: nondimensional maximum
magnitude of damping
mp_physics=2
Purdue Lin et al. scheme5-class microphysics including graupel1.2 includes ice sedimentation
mp_physics=3
NCEP 3-class schemeFrom RSM scheme (Hong)3-class microphysics with iceIce processes below 0 deg C1.2 includes ice sedimentation
mp_physics=4
NCEP 5-class schemeAlso from RSM scheme (Hong)5-class microphysics with iceSupercooled water and snow melt1.2 includes ice sedimentation
mp_physics=5
Ferrier (new Eta) schemeOne prognostic total condensate variableDiagnostic ice and water species and liquid fractions
ra_lw_physics=1
RRTM scheme from MM5Spectral schemeK-distributionLook-up table fit to accurate calculationsInteracts with cloudsOzone from climatology
ra_lw_physics=99
GFDL longwave scheme used in EtaSpectral scheme from global modelAlso uses tablesInteracts with cloudsOzone from climatology
ra_sw_physics=1
MM5 shortwave (Dudhia)Simple downward calculationClear-sky scatteringWater vapor absorptionCloud albedo and absorption
bl_sfclay_physics=1
Monin-Obukhov similarity theoryTaken from standard relations used in MM5 MRF PBLProvides exchange coefficients to surface (land) schemeShould be used with bl_pbl_physics=1
bl_sfclay_physics=2
Monin-Obukhov similarity theoryModifications due to JanjicTaken from standard relations used in Eta model, including Zilitinkevich thermal roughness lengthShould be used with bl_pbl_physics=2
bl_surface_physics=1
5-layer thermal diffusion model from MM5Predict ground temp and soil tempsThermal properties depend on land useNo effect for waterProvides heat and moisture fluxes for PBL
bl_surface_physics=2
OSU/MM5 Land Surface ModelVegetation effects includedPredicts soil temperature and soil moisture in four layersPredicts snow cover and canopy moistureDiagnoses skin tempProvides heat and moisture fluxes for PBL
bl_pbl_physics=1
MRF PBL scheme from MM5Non-local mixing in dry convective boundary layerDepth of PBL determined from critical bulk RiVertical diffusion depends on Ri in free atmosphere
bl_pbl_physics=2
Mellor-Yamada-Janjic (Eta) PBL1.5-order, level 2.5, TKE predictionLocal vertical mixing in boundary layer and free atmosphere
cu_physics=1
New Kain-Fritsch As in MM5 and Eta test versionIncludes shallow convectionCAPE removal time scaleMass flux type with updrafts and downdrafts, entrainment and detrainmentIncludes cloud detrainment
cu_physics=2
Betts-Miller-JanjicAs in Eta modelAdjustment type schemeNo explicit updraft or downdraft
cu_physics=99
Kain-Fritsch As in MM5CAPE removal time scaleMass flux type with updrafts and downdrafts, entrainment and detrainmentIncludes cloud detrainment
(1) Level 2.5 TKE
(2) Level 2
3d Smagorinsky
(3) Constant
diffusion
Subgrid Turbulence
IN WORKING ON PLANNED
2d Smagorinsky(mesoscale)
Microphysics
(1) Kessler
(2) Lin et al. [Purdue]
(3) Cloud3 [NCEP]
(4) Cloud5 [NCEP]
(5) Eta (Ferrier)
(6) Zhao-Carr(old eta)
Goddard
New Cloud3/5
Lin et al. 2
Reisner 2
IN WORKING ON PLANNED
Radiation
(1) RRTM
(2) Eta (GFDL)
IN WORKING ON PLANNED
Goddard
Lon
gS
hor
t (1) Dudhia [MM5]
(2) Goddard
(3) Eta (GFDL)
Boundary Layer
(1) MRF
(2) Mellor-Yamada-
Janjic
(1) MRF Similarity
(2) Eta Similarity
Bou
nd
ary
laye
rS
urf
ace
laye
rL
and
surf
ace (1) 5-layer soil temp
(2) OSU/MM5 LSM
IN WORKING ON PLANNED
TGS LSM (RUC)Unified NOAH LSM
New MRF
CLM