DQRID : D080306.6
Start DateStart TimeEnd DateEnd Time
03/02/2005163504/26/20061635
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Subject:
SGP/SMOS/E27 - Incorrect Offset for Wind Directon
DataStreams:sgp30smosE27.b1, sgp1smosE27.b1
Description:
An incorrect offset of 7 degrees was subtracted from the wind direction to correct for 
misalignment of the towers to true north. The wind direction data may be corrected but the 
vector averaged wind speed cannot. Subsequent audits have highlighted problems with past 
measurements of tower alignments.  All corrections to wind direction are being removed and 
Users are directed to view the Instrument Handbook for a table listing all tower 
alignment deviations from true north.  Users can adjust the data at their discretion.
Suggestions: 
To correct for a negative offset in wind direction the following formula can
   be used:
   WindCalc = wdir + 7degrees
   if WindCalc > 360
   then
   Windcorr = WindCalc - 360
   Else
   Windcorr = WindCalc
Measurements:sgp30smosE27.b1:
  • Wind Direction(wdir)
  • Wind Speed (vector averaged)(wspd_va)
more
sgp1smosE27.b1:
  • Wind Direction(wdir)
  • Wind Speed (vector averaged)(wspd_va)
more

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