20060724: GFS changes

[Linda Miller]

426 
NOUS41 KWBC 241816
PNSWSH

TECHNICAL IMPLEMENTATION NOTICE 06-44...CORRECTED
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
215 PM EDT MON JUL 24 2006

TO:       FAMILY OF SERVICES /FOS/ SUBSCRIBERS...NOAA 
          WEATHER WIRE SERVICE /NWWS/ SUBSCRIBERS... 
          EMERGENCY MANAGERS WEATHER INFORMATION NETWORK 
          /EMWIN/ SUBSCRIBERS...OTHER NATIONAL WEATHER 
          SERVICE /NWS/ CUSTOMERS AND PARTNERS...NWS 
          EMPLOYEES

FROM:     PAUL HIRSCHBERG
          CHIEF...SCIENCE PLANS BRANCH
          OFFICE OF SCIENCE AND TECHNOLOGY /OST/

SUBJECT:  CORRECTED: UPGRADES TO THE NATIONAL CENTERS FOR 
          ENVIRONMENTAL PREDICTION GLOBAL FORECAST SYSTEM 
          POSTPONED UNTIL AUGUST 22 2006.

REFER TO: TECHNICAL IMPLEMENTATION NOTICE /TIN/ 06-44
   TRANSMITTED ON JUNE 20 2006 AND TIN 06-44 /AMENDED/
          TRANSMITTED ON JULY 21 2006

CORRECTED TO DELETE REFERENCE IN THE AMENDED TIN 06-44 TO THE 
HYBRID COORDINATE SYSTEM BEING PART OF THE GFS UPGRADE PACKAGE.

THE TEXT OF THE ORIGINAL AMENDED TIN...MINUS INFORMATION ON THE 
HYBRID COORDINATE CHANGE...IS GIVEN BELOW.

THIS NOTICE AMENDS TIN 06-44 TO DELAY THE IMPLEMENTATION 
DATE OF THIS UPGRADE FROM JULY 25 2006 TO AUGUST 22 2006.  

IN ADDITION THE ORIGINAL NOTICE INDICATED THAT THE NATIONAL 
CENTERS FOR ENVIRONMENTAL PREDICTION /NCEP/ WOULD BE 
SWITCHING THE GLOBAL FORECAST SYSTEM /GFS/ TO USE A HYBRID 
COORDINATE SYSTEM FOR ITS PROCESSING. THIS CHANGE HAS BEEN 
REMOVED FROM THE UPGRADE PACKAGE. THE GFS WILL CONTINUE TO 
BE PRODUCED IN THE PRESSURE COORDINATE SYSTEM.

THE ORIGINAL NOTICE...MINUS INFORMATION ON THE HYBRID 
COORDINATE CHANGE...IS GIVEN BELOW.

ON THE ABOVE EFFECTIVE DATE...BEGINNING WITH THE 1200 
COORDINATED UNIVERSAL TIME /UTC/ RUN...THE NATIONAL CENTERS 
FOR ENVIRONMENTAL PREDICTION /NCEP/ WILL IMPLEMENT UPGRADES 
TO ITS GLOBAL FORECAST SYSTEM /GFS/ MODEL.  THESE UPGRADES 
ARE AS FOLLOWS:

     - ADDITION OF NAVAL RESEARCH LABORATORY /NRL/ OZONE
       PHYSICS
     - ADDITION OF GLACIAL ICE PHYSICS WITH MODIFIED 
       OROGRAPHY
     - IMPROVED GLOBAL SNOW ANALYSIS /LESS INTERPOLATION/
     - CORRECTION TO SURFACE DOWNWARD LONGWAVE RADIATION,
     - CHANGE OF THE TIME-FILTER COEFFICIENT /0.85/
     - UPGRADES TO SURFACE CYCLING...COMPATIBLE WITH THE NEW
       SNOW ANALYSIS
     - USES EARTH SYSTEM MODELING FRAMEWORK /ESMF/
       SUPERSTRUCTURE
     - RESTART FILES ARE IN FULL PRECISION /FORECASTS ARE
       THUS REPRODUCIBLE/
     - WILL ALLOW MULTIPLE ENSEMBLE MEMBER FORECASTS TO BE
       RUN CONCURRENTLY

THE PURPOSE OF THESE CHANGES IS TO:

     - USE ESMF
     - MAKE MINOR IMPROVEMENTS /TIME FILTER COEFFICIENT AND
       DOWNWARD LONGWAVE RADIATION/                                 
     - MAKE UPGRADES THAT HAVE BEEN PLANNED FOR A WHILE /NEW 
       SNOW ANALYSIS/
     - MAKE PHYSICS CHANGES /OZONE, GLACIAL ICE/.

THE EXPECTED IMPACTS ARE GENERALLY MINOR...THOUGH 
ULTRAVIOLET /UV/ FORECASTS SHOULD BE IMPROVED BY THE CHANGED 
OZONE SCHEME.

THE NCEP ENVIRONMENTAL MODELING CENTER /EMC/ BEGAN RUNNING 
PARALLEL FORECASTS ON MAY 9 2006 AND IS CURRENTLY UP TO REAL 
TIME.  STATISTICAL SCORE COMPARISONS FOR BOTH THE 
OPERATIONAL AND NEW GFS ARE AVAILABLE AT THE FOLLOWING WEB 
SITES /USE LOWER CASE/:

EMC.NCEP.NOAA.GOV/GC_WMB/WD20XW/HTML_DIE/INDEX_PRYO_NEW.HTML
     
EMC.NCEP.NOAA.GOV/GC_WMB/WD20XW/HTML_LINE/INDEX_PRYO_NEW.HTML

IF YOU HAVE QUESTIONS ABOUT THESE CHANGES...PLEASE CONTACT: 

MARK IREDELL
NCEP...GLOBAL MODELING BRANCH
CAMP SPRINGS MARYLAND
PHONE: 301 763 8000 X7231
EMAIL: MARK.IREDELL at NOAA.GOV

OR

BRENT GORDON
NCEP...PRODUCTION MANAGEMENT BRANCH
CAMP SPRINGS MARYLAND
PHONE: 301 763 8000 X7193
EMAIL: BRENT.GORDON at NOAA.GOV

THIS AND OTHER NWS TECHNICAL IMPLEMENTATION NOTICES ARE 
AVAILABLE ONLINE AT /USE LOWER CASE LETTERS/:

HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM

$$
NNNN

-- 
Linda Miller - lmiller at unidata.ucar.edu
Community Services, Unidata
University Corporation for Atmospheric Research
P.O. Box 3000
Boulder, CO 80307-3000
303-497-8646 fax: 303-497-8690 


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