0050712: replacement of ASOS wind sensor

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: 0050712: replacement of ASOS wind sensor
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Tue, 12 Jul 2005 11:03:41 -0600

NOUS41 KWBC 121538
PNSWSH

TECHNICAL IMPLEMENTATION NOTICE 05-51
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
1135 AM EDT TUE JUL 12 2005

TO:     FAMILY OF SERVICES /FOS/ SUBSCRIBERS...NOAA WEATHER WIRE
        SERVICE /NWWS/ SUBSCRIBERS...EMERGENCY MANAGERS WEATHER
        INFORMATION NETWORK /EMWIN/ SUBSCRIBERS...NOAAPORT
        SUBSCRIBERS...OTHER NATIONAL WEATHER SERVICE /NWS/
        CUSTOMERS AND PARTNERS...AND NWS EMPLOYEES

FROM:   MIKE CAMPBELL
        CHIEF...OCWWS OBSERVING SERVICES DIVISION

SUBJECT:REPLACEMENT OF AUTOMATED SURFACE OBSERVING SYSTEM WIND
        SENSOR

THE FOLLOWING CHANGES HAVE NO 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 24 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 24 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 NEW SENSOR... KNOWN AS THE ICE FREE WIND /IFW/SENSOR... WILL
BE DEPLOYED AT ALL ASOS LOCATIONS OVER A 12 MONTH PERIOD
BEGINNING LATER THIS MONTH ...MORE SPECIFIC INFORMATION WILL BE
ISSUED BY THE RESPONSIBLE WEATHER FORECAST OFFICE FOR EACH
INDIVIDUAL SITE WHEN THE IFW IS IMPLEMENTED. THESE SITE SPECIFIC
NOTICES WILL INDICATE THE DATE OF TRANSITION TO THE IFW AND
CONTAIN THE FOLLOWING INFORMATION:

    SID  STATION NAME        CONFIGURATION       DEPLOYMENT DATE

FURTHER INFORMATION ON IFW IMPLEMENTATION PLANS AND STATUS CAN BE
FOUND ON THE SURFACE OBSERVATIONPROGRAM WEB PAGE AT (USE LOWER
CASE LETTERS EXCEPT...PLEASE NOTE THAT S IN SURFACE IS IN UPPER
CASE):

WWW.NWS.NOAA.GOV/OPS2/SURFACE/INDEX.HTM

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

    DAVID MANNARANO
        ASOS IMPLEMENTATION MANAGER
        PHONE:  301-713-2093 X103
        E-MAIL:  DAVID.MANNARANO@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
ONLINE AT /USE LOWER CASE/:

    HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM

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