-------- Original Message --------
213
NOUS41 KWBC 081222
PNSWSH
TECHNICAL IMPLEMENTATION NOTICE 08-31 AMENDED
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
822 AM EDT THU MAY 8 2008
TO: SUBSCRIBERS:
-FAMILY OF SERVICES
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
OTHER NWS PARTNERS...USERS AND EMPLOYEES
FROM: JASON TUELL
SCIENCE PLANS BRANCH CHIEF
OFFICE OF SCIENCE AND TECHNOLOGY
SUBJECT: AMENDED: GLOBAL FORECAST SYSTEM CHANGES:
EFFECTIVE DATE CHANGED TO JUNE 3 2008
REFER TO: TECHNICAL IMPLEMENTATION NOTICE /TIN/ 08-31
TRANSMITTED ON APRIL 2 2008
AMENDED TO DELAY THE IMPLEMENTATION DATE FROM MAY 13 2008 TO
JUNE 3 2008 TO ALLOW FOR ADDITIONAL TESTING. FURTHER DELAY IS
POSSIBLE DEPENDING ON TEST RESULTS. ANOTHER AMENDMENT WILL BE
ISSUED IF THERE IS NECESSARY. THE ORIGINAL NOTICE...WITH A
REVISED DATE...IS GIVEN BELOW:
EFFECTIVE JUNE 3 2008...BEGINNING WITH THE 1200 COORDINATED
UNIVERSAL TIME /UTC/ RUN...SEVERAL CHANGES WILL BE MADE TO THE
GLOBAL FORECAST SYSTEM /GFS/ MODELING SYSTEM. THESE CHANGES
ARE BEING MADE TO IMPROVE MODEL PERFORMANCE.
THE FOLLOWING FOUR CHANGES INVOLVE A SIGNIFICANT UPGRADE IN
THE CONSISTENCY AND ACCURACY OF THE MODEL RADIATION
PARAMETERIZATIONS:
1. HOURLY RRTM1 LONGWAVE RADIATION RRTM SHORTWAVE RADIATION
2. MAXIMUM-RANDOM CLOUD OVERLAP FOR SHORTWAVE GENERALIZED
AEROSOL TREATMENT AND REALISTIC CO2
3. MINOR ADJUSTMENTS OF OROGRAPHIC GRAVITY WAVE VARIANCE
RANGE LIMITS AND MOUNTAIN BLOCKING BUG FIX
4. ENTHALPY THERMODYNAMIC PROGNOSTIC VARIABLE WHICH ALLOWS
FOR GREATER FLEXIBILITY AND IN CARRYING ATMOSPHERIC
CONSTITUENTS
THE ANALYSIS CHANGES INCLUDE:
1. ADDING WINDSAT NEAR SURFACE WINDS
2. ADDING NOAA-18 SBUV/2 OZONE
3. FOTO /FIRST-ORDER TIME-EXTRAPOLATION TO OBSERVATIONS/
4. VARIATIONAL QC
5. CHANGE IN LAND/SNOW/ICE SKIN TEMPERATURE VARIANCE
6. FLOW DEPENDENT RE-WEIGHTING OF BACKGROUND ERROR VARIANCES
7. BUG FIXES TO PROCESSING OF COSMIC GPSRO DATA...GROSS
CHECK...AND ADJUSTMENT OF OBSERVATION ERROR FOR VERTICALLY
DENSE OBSERVATIONS
8. CODE AND SCRIPT OPTIMIZATION
OTHER OUTPUT CHANGES INCLUDE:
1. THE INTERNAL MODEL SPECTRAL /SIGMA/ FILE IS CHANGING ITS
FORMAT SLIGHTLY. THIS FILE IS NOT USED FOR PRODUCTS. ONLY
ITS HEADER INFORMATION IS CHANGING. USERS GUIDE AND
SAMPLE CODE AND FILES CAN BE FOUND AT /USE LOWER CASE
LETTERS/:
HTTP://WWW.EMC.NCEP.NOAA.GOV/GMB/IREDELL/GFS/SAMPLE2008/
2. THERE ARE NO OTHER OUTPUT CHANGES. NOTABLY NO GRIB
PRODUCTS ARE CHANGING.
THE COMBINED IMPACT OF THESE CHANGES HAS LED TO THE FOLLOWING
IMPROVEMENTS IN MODEL PERFORMANCE:
1. IMPROVED SKILL IN EXTRATROPICAL 3-DAY FORECAST PERFORMANCE
AT 500 MB...PARTICULARLY IN THE SOUTHERN HEMISPHERE BETTER
LOWER STRATOSPHERIC THERMODYNAMIC STRUCTURE
2. MORE DETAILS ABOUT THESE CHANGES CAN BE SEEN AT
/USE LOWERCASE/:
HTTP://WWW.EMC.NCEP.NOAA.GOV/GMB/WX24FY/VSDB_EXP/SUMMER07/
DATA DELIVERY TIMING WILL NOT BE IMPACTED BY THIS
IMPLEMENTATION. DATA VOLUMES ARE NOT EXPECTED TO INCREASE.
SIGNIFICANT DATA CONTENT CHANGES ARE NOT EXPECTED.
THESE MODEL CHANGES WILL IMPACT ALL DISSEMINATION ROUTES WHICH
INCLUDE NOAAPORT...THE NWS PUBLIC FTP SERVER AND THE NCEP
PUBLIC FTP SERVER. A CONSISTENT PARALLEL FEED OF DATA WILL
BECOME AVAILABLE ON THE NCEP FTP SERVER ON APRIL 1 2008 AT THE
FOLLOWING URL /USE LOWERCASE/:
FTP://FTP.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PARA
NCEP WOULD ENCOURAGE ALL USERS TO ENSURE THEIR DECODERS ARE
FLEXIBLE AND ARE ABLE TO ADEQUATELY HANDLE CHANGES IN CONTENT
ORDER...PARAMETER FIELDS CHANGING ORDER...CHANGES IN THE
SCALING FACTOR COMPONENT WITHIN THE PDS OF THE GRIB FILES AND
ANY VOLUME CHANGES THAT MAY BE FORTHCOMING. THESE ELEMENTS MAY
CHANGE WITH FUTURE NCEP MODEL IMPLEMENTATIONS. NCEP WILL MAKE
EVERY ATTEMPT TO ALERT USERS TO THESE CHANGES BEFORE
IMPLEMENTATIONS.
FOR QUESTIONS CONCERNING THESE CHANGES...PLEASE CONTACT:
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
NWS TECHNICAL IMPLEMENTATION NOTICES ARE ONLINE AT
/USE LOWER CASE/:
HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM
$$