Sonic wind component u

The data contains values for u direction of the wind in a sampling frequency of 20 Hz. Erroneour spikes were filterd in two steps.

1. Define moving window uₓ = u(i-3:i+3)
2. If u(i)-mean(uₓ) > 2*std(uₓ):u(i) = NaN

Frozen detectors resulted in continuous zero values (not filtered). The wind speed and direction were calculated as follows:

wind speed = sqrt(u² + v²) wind direction = 180° + (180° / PI)* arctan2 (-u, -v)