CCPP Updates for the SRW App v2.2.0 Release
Here is what’s new in CCPP Physics for the UFS SRW v2.2.0 public release.
General Updates
Added RAP suite (
FV3_RAP
) as a new supported suite (documentation here)Added the Community Land Model (CLM) lake model in the HRRR suite (
FV3_HRRR
)
Thompson Microphysics Scheme
Reduced ice generation supersaturation requirement from 0.25 to 0.15 to generate more ice at the upper levels and reduce the outgoing longwave radiation bias
Divided cloud number concentration into two parts (over land and others). Reduced number concentration over ocean to a smaller number (50/L) from its previous default (100/L). Both changes were made to reduce excessive surface downward shortwave radiative flux off coastal regions including the Southeast Pacific
Implemented small fixes to the minimum size of snow and collision constants
Note
The above improvements were tested with the non-aerosol option, so results with the aerosol-aware Thompson (used in the SRW App) may vary.
NoahMP Land Surface Model
Option for using the unified frozen precipitation fraction in NoahMP.
Diagnostic 2-meter temperature and humidity now based on vegetation and bare-ground tiles (new namelist option
iopt_diag
)Bug fixes for GFS-based thermal roughness length scheme
New soil color dataset introduced to improve soil albedo to reduce the large warm bias found in the Sahel desert
Wet leaf contribution factor is included
Leaf-area index now depends on momentum roughness length
RUC Land Surface Model
Initialization of land and ice emissivity and albedo with consideration of partial snow cover
Initialization of water vapor mixing ratio over land ice
Initialization of fractions of soil and vegetation types in a grid cell
Changes in the computation of a flag for sea ice: set to true only if
flag_cice=.false
(atmosphere uncoupled from the sea ice model).Separate variables for sea ice, for example:
snowfallac
is replaced withsnowfallac_ice
Solar angle dependence of albedo for snow-free land
Coefficient in soil resistance formulation (Sakaguchi and Zeng, 2009) raised from 0.7 to 1.0 to increase soil resistance to evaporation
Computation of snow cover fraction and snow thermal conductivity updated
GFS Scale-Aware TKE-EDMF PBL and Cumulus Schemes
Parameterization to represent environmental wind shear effect added to reduce excessively high hurricane intensity
Entrainment rates enhanced proportionally to the sub-cloud or PBL-mean TKE when TKE is larger than a threshold value
Entrainment rate is increased as a function of vegetation fraction and surface roughness length to enhance underestimated CAPE
MYNN-EDMF PBL Scheme
Small increase of buoyancy length scale in convective environments
Patch for ensuring non-zero cloud fractions for all grid cells where cloud mixing ratio is greater than 1e-6 or ice mixing ratio is greater than 1e-9
Subgrid-Scale (SGS) Clouds Scheme
Bug fix for cloud condensate input into RRTMG radiation
New code section for use with SAS convection scheme
Cloud fraction now computed as a mix between the area-dependent form and the modified Chaboureau and Bechtold (2005) form
Adjusted limit for the boundary flux functions
MYNN Surface-layer Scheme
Reintroduced friction velocity averaging over water to reduce noise in 10-m winds in the hurricane regime
Grell-Freitas Scale and Aerosol Aware Convection Scheme
Update for aerosol-awareness (experimental)
Scale-awareness turned off when explicit microphysics is not active anywhere in the column
Convection is completely suppressed at grid points where the MYNN PBL scheme produces shallow convection
Radar reflectivity considers mass flux PDF as well as whether scale-awareness is turned on at the grid point in question
Unified Gravity Wave Physics Scheme
Optional diagnostic for tendencies computed. They can be switched on by setting the following namelist variables to
“.true.”
:ldiag3d
andldiag_ugwp
Attention
The improvements in Thompson cloud microphysics, NoahMP land surface model, GFS TKE-EDMF and cumulus schemes were tested in the UFS global configuration, so results in the UFS limited-area configuration (SRW) may vary.