Mesoscale Parallel Experiment Change Log

Experiment Name:  North American WRF-NMM with various physics and/or analysis changes

When Who What
2008/08/07/12 Lin
  • The 12z 6/13 change (use of the CPC daily gauge analysis in /dcom in the calculation of the long-term water budget used to bias-adjust the precipitation analyses used in the NDAS) was implemented into the operational NDAS as of this date.
    • 2008/08/01/12 Carley, Ferrier, Janjic, Wong, Mitchell, Rogers
  • Changes to land-sfc physics:
    1. Let ETP (potential evaporation) decrease linearly with Bulk Richardson # under stable condition, and weighted by snow coverage.
    2. Let DQSDT2 (slope of saturated humidity function wrt temperature) decrease linearly with snow coverage.
  • In the radiation parameterization, the absorbtion coefficients for water and ice have been doubled to 1600 and 1000, respectively
  • Revert back to using operational shallow convection parameterization
  • Restarted using cycled land-states and satellite radiance bias-corrections from NDASX
    • 2008/07/17/18 Rogers, Wu
  • Due to a mirroring glitch, the observation error file used by the new GSI analysis was not mirrored to mist until this cycle . For all parallel runs on mist (12z 7/9/2008 - 00z 7/16/2008) no conventional data except for surface pressure data was used.
    • 2008/07/03/12 Janjic
  • New shallow convection modified to use "swapsoft2" clouds. For soft2 clouds:
    1. RHref=RHmean[2w(p-ptop)/(pbot-ptop)+(1-w)], where
      1. w=.05
      2. RHmean=mean RH w.r.t. pressure between cloud base and cloud top
    2. "swapsoft" clouds : the new cloud is only used at swap points, at straight points the old cloud is used
    • 2008/07/01/12 Ferrier, Gayno, Janjic, Rogers
  • Changes to WRF-NMM forecast model:
    1. The model for shallow convection is modified to be a plume, or an ensemble of plumes extending from cloud base to cloud top that are determined in the same way as in the current scheme. The air in the cloudy grid boxes is mixed in such a way that RH does not change with height. The temperature gradient within the cloud is a weighted mean of the ambient temperature gradient and the moist adiabatic temperature gradient, where the weights depend on RH. Note that with a cloud like this we cannot have almost saturated air with almost dry adiabatic temperature lapse rate that we occasionally see with the current scheme. As before, the enthalpy is conserved.
    2. The WRF MYJPBL, PBL driver, and the NMM's TURBL subroutine were modified to mix each hydrometeor species separately in the vertical. The current production code only mixes cloud liquid water.
    3. To apply vertical diffusion for separate water species, the subroutine VDIFH has been changed so that (a) it can handle an arbitrary number of species, (b) the counter gradient option can be applied to some or all of the species if desired, and (c) option to set to zero some or all of the surface fluxes is also made available.
  • Begin use of the AFWA 1/16 bedient snow depth analysis and a new version of the NAM_SNO2MDL code to process this data.
    • 2008/06/30/18 Wu
  • Begin use of METOP radiance data in the GSI analysis
    • 2008/06/16/12 Rogers, Pyle, Ferrier
  • Begin use of WPS (instead of WRF-SI) codes to process GDAS first guess GRIB files into a WRF input file used as a first guess to the first (tm12) GSI analysis in the NDAS
    • 2008/06/13/12 Lin
  • In the calculation of the long-term water budget used to bias-adjust the precipitation analyses used in the NDAS (as input to WRF-NMM land-sfc model), begin use of the CPC daily gauge analysis in /dcom. The new script converts it to GRIB on the fly, then checks for size of the GRIB'd file to prevent a faulty analysis from being used in long-term water budget calculation. Using the original CPC daily analysis, rather than the pre-GRIB'd version (the conversion to GRIB is done twice a day on a fixed schedule), will allow late-arriving or re-made CPC analyses to be used in the budget calculation. The additional screening performed in the new script will prevent bad analysis files (nearly all of them are less than 95,000 bytes when GRIB'd) from entering the long term budget calculations. These two changes will result in a more accurate long-term budget array and a more precise adjustment to hourly precipitation input used in the NDAS data assimilation.
    • 2008/06/11/12 Wu, Rogers
  • Begin use of latest (4Q 2008) version of the GSI analysis code
    • 2008/04/22/18 Rogers
  • Assimilation of AIRS satellite radiance data was turned on in the operational NDAS/NAM as of this cycle. It was not implemented as intended on 31 March 2008 due to a script error. To ensure a clean comparison to this parallel, the cycled NDASY were restarted from the ops NDAS restart file (land-states only) and ops NDAS satellite bias correction files as of this cycle date.
    • 2008/03/31/18 Rogers
  • NAM Winiter 2008 change package implemented (all changes in NAMY except TAMDAR data and partial cycling).
  • Restart NDASY cycled land-states from Ops NDAS
    • 2008/03/12/18 Treadon, Wu
  • Turn off assimilation of NOAA-16 AMSU-A brightness temperatures due to excessive noise (also turned off in ops NDAS/NAM)
    • 2008/02/25/08 Wu, Rogers
  • Turn on assimilation of TAMDAR/AMDAR aircraft data
  • Restart NDASY cycled land-states from NDASX (real-time NCO parallel expanded NAM run)
    • 2008/01/12/06 Rogers
  • Changed the surface update script to only update the SST, snow cover/depth, and sea-ice coverage at the start of the 06z NDAS, as is done in operations. Previously it was done at the start of each NDAS cycle (the default setting for partial cycling in a fully cycled NDAS system)
    • 2008/01/11/00 Wu, Treadon, Rogers
  • The 13 November 2007 change (which was intended to fix an error in the GSI analysis script that prevented the satbias_angle file from being updated) was not applied correctly due to an additional script error.
    • 2007/12/19/18 Treadon, Wu
  • Turned back on the assimilation of GOES-11 and GOES-12 1x1 sounder radiances.
    • 2007/12/18/12 Rogers
  • First NAMY run of partial cycling parallel running the same change package that is in NAMEXP. The NDAS was started with the following from NAMEXP:
    1. Land-sfc states
    2. Satellite radiance bias corrections
    3. Long-term precipitation budget file
  • Use NAMEXP 00z 12-36 h precip for OCONUS precip assimilation