20060928: ASOS wind sensor replacement-[Fwd: ADMIN NOTICE NOUS41 KWBC]

[Linda Miller]

-------- Original Message --------

971 
NOUS41 KWBC 281358
PNSWSH

TECHNICAL IMPLEMENTATION NOTICE 02-30A 
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC 
1000 AM EDT THU SEP 28 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 OF
          AVIATION DATA AND FORECASTS...NWS EMPLOYEES 

FROM:     MIKE CAMPBELL 
          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 FOLLOWING ASOS LOCATIONS HAVE OR WILL TRANSITION TO THE IFW 
CONFIGURATION ON THE INDICATED DATES: 

HTL HOUGHTON LAKE ASOS SEPTEMBER 29, 2006

IF YOU HAVE ANY QUESTIONS ABOUT THIS CHANGE...PLEASE CONTACT ONE OF 
THE FOLLOWING INDIVIDUALS AT NWS HEADQUARTERS: 

JAMES HEIL 
SURFACE OBSERVATIONS FOCAL POINT 
PHONE: 301-713-1792 X140 
E-MAIL: JAMES.HEIL at NOAA.GOV 
OR 
RICHARD AHLBERG 
ASOS PLANNED PRODUCT IMPROVEMENT PROGRAM MANAGER 
PHONE: 301-713-1975 X160 
E-MAIL: RICHARD.AHLBERG at 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 
$$ 
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-- 
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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