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@NOAA.GOV OR RICHARD AHLBERG ASOS PLANNED PRODUCT IMPROVEMENT PROGRAM MANAGER PHONE: 301-713-1975 X160 E-MAIL: RICHARD.AHLBERG@NOAA.GOV. 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 $$ NNNN