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-------- Original Message --------862 NOUS41 KWBC 121524
PNSWSH TECHNICAL IMPLEMENTATION NOTICE 07-21 NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC 1120 PM EDT THU APR 12 2007TO: 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: NCEP GLOBAL FORECAST SYSTEM MODEL UPGRADE: EFFECTIVE
MAY 1 2007
EFFECTIVE TUESDAY MAY 1 2007...BEGINNING WITH THE 1200 COORDINATED UNIVERSAL TIME /UTC/ RUN...THE NATIONAL CENTERS FOR ENVIRONMENTAL PREDICTION /NCEP/ WILL UPGRADE THE GLOBAL FORECAST SYSTEM /GFS/ TO IMPROVE ITS ACCURACY AND PRODUCTS.
THIS UPGRADE WILL INVOLVE IMPROVEMENTS TO BOTH THE ANALYSIS AND FORECAST OF THE GFS. DETAILS OF THESE CHANGES ARE AS FOLLOWS:
ANALYSIS CHANGES:1. REPLACE SPECTRAL STATISTICAL INTERPOLATION /SSI/ ANALYSIS SYSTEM WITH GRIDPOINT STATISTICAL INTERPOLATION /GSI/ ANALYSIS SYSTEM. 2. USE OF INCREASED OBSERVATIONS INCLUDING FULL RESOLUTION ATMOSPHERIC INFRARED SOUNDER /AIRS/ DATA...CONSTELLATION OBSERVING SYSTEM FOR METEOROLOGY...IONOSPHERE AND CLIMATE /COSMIC/ GLOBAL POSITIONING SYSTEM RADIO OCCULTATION /GPSRO/ DATA.
MODEL CHANGES: 3. MODIFY SIGMA COORDINATE SYSTEM TO A HYBRID SIGMA-PRESSURE COORDINATE SYSTEM. 4. UPDATED GFS RADIATION MODULE PRODUCT CHANGES:5. SURFACE FLUX FILES HAVE 30 NEW RECORDS MAINLY FOR HYDROLOGICAL USE
6. CHANGE OUTPUT OF GLOBAL DIAGNOSTIC ASSIMILATION SYSTEM /GDAS/ FROM 3-HOURLY TO HOURLY
7. MODEL TO NATIVE OUTPUT FILE WILL CHANGE FROM A SIGMA SPECTRAL BINARY FILE TO A HYBRID SPECTRAL BINARY FILE
PLEASE NOTE THAT THERE WILL BE NO CHANGES TO THE GFS PRODUCTS BEING SENT OVER NOAAPORT WITH THIS UPGRADE.
EXPECTED IMPROVEMENTS/CHANGES: THE GFS FORECAST SHOULD HOLD THE ASIAN JET EAST OF THE HIMALAYASBETTER. THE GFS FORECAST SHOULD BE SLIGHTLY IMPROVED OVERALL IN THE STRATOSPHERE. THE OVERALL TROPICAL SKILL OF THE GFS FORECASTS SHOULD IMPROVE. THE EXTRATROPICAL SKILL SHOULD IMPROVE IN THE SHORT LEAD TIMES BUT BE ABOUT THE SAME IN THE MEDIUM RANGE. THE UNIFIED GSI ANALYSIS SYSTEM ENABLES NEW OBSERVATION SYSTEMS AND IS MORE ADAPTABLE FOR FUTURE UPGRADES.
RETROSPECTIVE EVALUATION:THE GFS SYSTEM HAS BEEN RETROSPECTIVELY EVALUATED FOR THE FOLLOWING PERIODS:
JULY 1 2005 OCTOBER 31 2005 SEPTEMBER 1 2006 OCTOBER 31 2006 NOVEMBER 1 2006 JANUARY 31 2007RESULTS FROM THESE RETROSPECTIVE RUNS CAN BE VIEWED AT /USE LOWER CASE LETTERS/:
HTTP://WWWT.EMC.NCEP.NOAA.GOV/GMB/PARA/PARALOG.GSIHYBRID.HTMLNCEP CENTRAL OPERATIONS IS CURRENTLY RUNNING A REAL-TIME PARALLEL RUN VERSION OF THE GFS WITH THESE UPGRADES. RESULTS FROM THESE PARALLEL RUNS CAN BE VIEWED AT /USE LOWER CASE LETTERS/:
HTTP://WWW.NCO.NCEP.NOAA.GOV/PMB/NWPARA/ANALYSISTHE EFFECTIVE DATE OF THIS CHANGE IS SOONER THAN SPECIFIED BY NWS POLICY. THE SHORTER ADVANCE LEAD TIME WAS CAUSED BY THE NECESSITY TO CONDUCT AN EVALUATION OF THE GFS MODEL OUTPUT STATISTICS /MOS/ GUIDANCE PRODUCTS. RESULTS OF THE EVALUATION CONCLUDED THAT THERE WILL BE LITTLE IF ANY IMPACT ON GFS MOS GUIDANCE PRODUCTS. THE SHORTER LEAD TIME WAS APPROVED BECAUSE IT IS EXPECTED THAT USERS WILL NOT HAVE TO MAKE MAJOR ADJUSTMENTS TO ACCOMMODATE THESE CHANGES. IF YOU HAVE ANY QUESTIONS ABOUT THESE CHANGES...PLEASE CONTACT
DR. MARK IREDELL NCEP...GLOBAL MODELING BRANCH CAMP SPRINGS MARYLAND PHONE: 301 763 8000 X7231 EMAIL: MARK.IREDELL@xxxxxxxx OR KEN CAMPANA NCEP...GLOBAL MODELING BRANCH CAMP SPRINGS MARYLAND PHONE: 301 763 8000 X7228 EMAIL: KENNETH.CAMPANA@xxxxxxxx
THIS AND OTHER NWS TECHNICAL IMPLEMENTATION NOTICES ARE AVAILABLE ONLINE AT /USE LOWER CASE LETTERS/: HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM $$ NNNN
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