[nws-changes] 20080911: RUC model changes

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 20080911: RUC model changes
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Thu, 11 Sep 2008 10:28:56 -0600

NCEP Model Evaluation Subscribers,

The changes include:

  1. Upgrades to algorithms for RUC analysis

        3. Assimilation of TAMDAR aircraft observations including
           moisture observations
        4. Revision to observation error and background error for
           moisture observations
        5. Improved QC based on observation-background differences
  2. Upgrades to algorithms for RUC model
        1. Specification of latent heating from radar reflectivity
           during pre-forecast diabatic digital filter initialization
           (DFI) already in RUC model
        2. Use of RRTM longwave radiation parameterization replacing
           current Dudhia longwave radiation, warm bias at surface in
           warm season, and decreasing cold bias at night over snow cover
        3. Modifications to Grell-Devenyi convective parameterization
           to reduce excessive areal coverage for light precipitation
           and to introduce non-local subsidence warming
        4. Modification to RUC land-surface model for snow density to
           prevent excessive surface temperature over fresh snow
  3. Upgrade to RUC post-processing code
        1. Add 3 reflectivity fields to isobaric (ruc_presm) output
           fields for max, 1-km, and 4-km levels, similar to those
           products already produced for the NAM
        2. Add accumulated total precipitation and snow fields, also
           following NAM fields
        3. Modify ceiling diagnostic to avoid excessive LIFR (Low
           Instrument Flight Rules) conditions. Ed. Pre-processing of
           3-d radar reflectivity to ~13km resolution from
           higher-resolution tiles **


*N**ear Rea**l-Time Parallel Data*

Beginning Tuesday 16 September 2008, parallel data will be at:

HTTP:
http://www.ftp.ncep.noaa.gov/data/nccf/com/ruc/test/ruc2a.YYYYMMDD

In addition, we are sending GEMPAK data to the WOC at:

FTP:

HTTP:
http://www.ftp.ncep.noaa.gov/data/nccf/com/nawips/test/ruc2.YYYYMMDD


There are no major scientific changes in this package.  We will make the
model output available for 30 days starting Tuesday, 16 September so that
end-users of the RUC data can verify that no unforeseen changes
have been introduced.

Any comments on this proposed change will be appreciated. Any feedback
you wish to provide during the evaluation period should be emailed to

Thanks

Dan Starosta

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