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Compared 2D sonic 10m wind directions to 3m sonic in order to orient 2D sonics. Only used winds from +/- 20 degrees from CSAT u axis and 10m wind speeds > 3 m/s (at FAR);
2 m/s at FLR.
Selected At FAR, selected the median value of Dir.10m + 230.1 - dir.3m . At FAR this is = 3.1 +/- 5.3 degrees. See attached plot. The 2D sonic is aligned with the boom, so need to add the boom direction, 230.1, minus the offset of 3.1 degrees, or 227 degrees to the 2D wind direction data.
At FLR, the 2D sonic was pointed nominally north, but must be off by 180 degrees. The median value of Dir.10m + 180 - dir.3m is = 6.6 +/- 5 deg (10m speed > 2 m/s). Thus need to add 180 - 6.6 = 173.4 deg to 2D wind direction data.
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