CV7 background error option
| Note: There is a known bug for this option in 3.7 and 3.7.1 that leads to incorrect results: see this page for a solution. |
WRFDA now has an additional background error option. This new option, CV7, uses a different set of control variables as the other standard options: u, v, temperature, pseudo relative humidity (RH_s), and surface pressure (P_s). The pseudo relative humidity is defined as Q/Q_b,s, where Qb,s is the saturated specific humidity from the background field. The procedure for generating be.dat background error files with GEN_BE is the same as for CV5, with an additional variable which must be set in the GEN_BE wrapper script: export NL_CV_OPTIONS=7. See the relevant section of the User's Guide) for more detailed instructions.
Radar assimilation updates
Note: There is a known bug in the original release version when use_radar_rqv = .true.: see this page or download the bugfix version 3.7.1 for a solution. |
As of version 3.7, WRFDA has an improved radar data assimilation capability: there are now two different options for assimilating radar reflectivity data.
The new reflectivity assimilation option (use_radar_rhv) is a scheme described in Wang et al, 2013. This option which assimilates rainwater mixing ratio that is estimated from radar reflectivity, described as an “indirect method” in the paper. This second option also includes an additional namelist option option (use_radar_rqv) that allows the assimilation of in-cloud humidity estimated from reflectivity using a method which is also described in Wang et al, 2013. use_radar_rqv also includes the assimilation of snow and graupel converted from reflectivity using formulas as described in Gao and Stensrud, 2012.
Additionally: previous versions did not allow for PREPBUFR-format conventional observations to be assimilated with radar data in ASCII format (ob.radar). Radar data can now be assimilated with most other data types, including conventional and satellite obs.
More detailed information about radar assimilation can be found in a new section of the User's Guide.
New WRFPLUS microphysics option
WRFPLUS now has two microphysics options to choose from for 4DVAR assimilation. The new scheme is a modified Kessler scheme. You can control which scheme is used with the following namelist option:
&physics
mp_physics_ad: mp_physics option for WRFPLUS.
98: Use original large-scale condensation microphysics (default)
99: Use new modified Kessler scheme
