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NOUS41 KWBC 252021
PNSWSH
PUBLIC INFO. STATEMENT...TECHNICAL IMPLEMENTATION NOTICE 02-30
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
420 PM EDT FRI OCT 25 2002
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 OF
AVIATION DATA AND FORECASTS...NWS EMPLOYEES
FROM: RAINER DOMBROWSKY
CHIEF...OBSERVING SERVICES DIVISION
SUBJECT: AUTOMATED SURFACE OBSERVING SYSTEM WIND SENSOR
REPLACEMENT
THE FOLLOWING CHANGES HAVE NO DIRECT IMPACT ON NOAA WEATHER WIRE
SERVICE SUBSCRIBERS
THE AUTOMATED SURFACE OBSERVING SYSTEM /ASOS/ PRODUCT IMPROVEMENT
PROGRAM WILL SOON DEPLOY A REPLACEMENT WIND SENSOR. THE NEW
SENSOR WILL REPORT WIND INFORMATION USING THE 3-SECOND WORLD
METEOROLOGICAL ORGANIZATION /WMO/ GUST STANDARD.
THE CURRENT ASOS WIND SENSOR /BELFORT 2000 / USES ROTATING CUPS
TO MEASURE WIND SPEED AND A VANE TO MEASURE WIND DIRECTION. OVER
A 2-MINUTE PERIOD...ASOS USES TWENTY-FOUR 5-SECOND AVERAGES TO
DETERMINE THE 2-MINUTE AVERAGE WIND SPEED AND DIRECTION. EVERY
MINUTE ASOS STORES THE HIGHEST 5-SECOND AVERAGE SPEED FOR THE
PAST MINUTE... ALONG WITH ITS DIRECTION... IN THE 12-HOUR ARCHIVE
FOR ADDITIONAL PROCESSING. THIS HIGHEST SPEED VALUE IS USED TO
DETERMINE IF A GUST AND/OR A PEAK WIND REMARK WILL BE REPORTED.
THE NEW ASOS WIND SENSOR /VAISALA 425NWS / IS A SONIC ANEMOMETER.
IT HAS NO MOVING PARTS AND WILL OPERATE BETTER IN WINTER WEATHER
CONDITIONS. AS WITH THE BELFORT SENSOR...OVER A 2-MINUTE
PERIOD...ASOS USES TWENTY-FOUR 5-SECOND AVERAGES TO DETERMINE THE
2-MINUTE AVERAGE WIND SPEED AND DIRECTION. BUT THE HIGHEST
3-SECOND RUNNING AVERAGE SPEED IS STORED FOR GUST AND PEAK WIND
PROCESSING.
WHILE THERE WILL BE LITTLE DIFFERENCE IN 2-MINUTE AVERAGE WIND
SPEED AND DIRECTION REPORTING...THE CHANGES IN GUST AND PEAK WIND
REPORTING MAY BE SIGNIFICANT. WE CAN EXPECT TO SEE MORE GUSTS
AND PEAK WINDS REPORTED WITH THE NEW SENSOR. THE MASS OF THE
MOVING PARTS IN EXISTING SENSORS LIMITS RESPONSIVENESS. THE NEW
SENSOR WILL BE MORE RESPONSIVE TO SHORT TERM GUSTS.
THE LAST ACTIVITY PRIOR TO IMPLEMENTATION AT 313 NWS AND 570 FAA
SPONSORED SITES IS A 20 SITE OPERATIONAL ACCEPTANCE TEST /OAT/.
THE OAT WILL BEGIN IN EARLY NOVEMBER OF 2002. EIGHTEEN /18/ OF
THE 20 OAT SITES WILL BE CONFIGURED WITH DUAL SENSORS...BOTH THE
EXISTING AND NEW SENSOR. THE EXISTING SENSOR WILL BE USED FOR
THE OFFICIAL OBSERVATION AT LOCATIONS WHERE DUAL SENSORS ARE
INSTALLED. INITIALLY THE NEW SENSOR OUTPUT WILL BE ARCHIVED FOR
ANALYSIS. WHEN THE ANALYSIS VALIDATES THE NEW SENSOR
PERFORMANCE...THE PROCESSING WILL BE CHANGED TO USE THE NEW
SENSOR FOR THE OFFICIAL OBSERVATION AND THE NEW SENSORS WILL BE
INSTALLED AT THE REMAINING 2 SINGLE SENSOR OAT SITES. BELFORT
SENSOR DATA WILL CONTINUE TO BE ARCHIVED AT THE DUAL SENSOR
SITES. THIS CHANGE IN THE USE OF SENSORS IS EXPECTED TO OCCUR IN
DECEMBER 2002. FOLLOWING A SUCCESSFUL OAT...FULL SCALE
DEPLOYMENT OF THE NEW SENSOR WILL BEGIN IN MARCH OF 2003 AND
EXTEND THROUGH SEPTEMBER 2006.
OAT LOCATIONS
SID STATION NAME CONFIGURATION DEPLOYMENT DATE
BRW BARROW AK DUAL NOVEMBER 2002
TKA TALKEETNA, AK DUAL NOVEMBER 2002
KTN KETCHICAN AK DUAL NOVEMBER 2002
SIT SITKA AK DUAL NOVEMBER 2002
CMX HANCOCK MI DUAL NOVEMBER 2002
GFK GRAND FORKS ND DUAL NOVEMBER 2002
TOP TOPEKA KS DUAL NOVEMBER 2002
BFF SCOTTSBLUFF NE DUAL NOVEMBER 2002
HUF TERRA HAUTE IN DUAL NOVEMBER 2002
OSH OSHKOSH WI DUAL NOVEMBER 2002
ARR CHICAGO/AURORA IL DUAL NOVEMBER 2002
FTW FORT WORTH TX DUAL NOVEMBER 2002
NEW NEW ORLEANS LA DUAL NOVEMBER 2002
LLJ CHALLIS ID DUAL NOVEMBER 2002
UAO AURORA OR DUAL NOVEMBER 2002
BLU BLUE CANYON CA DUAL NOVEMBER 2002
BTV BURLINGTON VT DUAL NOVEMBER 2002
CAR CARIBOU ME DUAL NOVEMBER 2002
ITO HILO HI SINGLE DECEMBER 2002
SFO SAN FRANCISCO CA SINGLE DECEMBER 2002
IF YOU HAVE ANY QUESTIONS ABOUT THIS CHANGE...PLEASE CONTACT ONE
OF THE FOLLOWING INDIVIDUALS AT NWS HEADQUARTERS:
TIMOTHY ROSS
SURFACE OBSERVATIONS PROGRAM MANAGER
PHONE: 301-713-1792 X114
E-MAIL: TIM.ROSS@xxxxxxxx
OR
RICHARD AHLBERG
ASOS PLANNED PRODUCT IMPROVEMENT PROGRAM MANAGER
PHONE: 301-713-1975 X160
E-MAIL: RICHARD.AHLBERG@xxxxxxxx.
THIS AND OTHER NWS TECHNICAL IMPLEMENTATION NOTICES ARE AVAILABLE
ON THE INTERNET AT /USE LOWER CASE/:
HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM
END
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