Reports

From 2021-05-26 to 2021-06-09 we conducted a sonic inter-comparison at SW.  We were checking that sonic sn 153805 (S2) which had fallen with the tower at Bouldin Corn was good.  This sonic had been previously compared at Tonzi but we were not able to collected 20Hz data there.  Here we collected 20Hz data from sonic S2 by connecting its analog outs the the 7700 analog inputs and were able to compare against the tower's sonic sn 120906 (S1).  There were two previous attempts to do this inter-comparison: 2021-03-25 to 2021-04-15 the analog pins were not correct for the 7700 inputs, and 2021-05-13 to 2021-05-26 the S2 mounting bolts were loose and the sonic tilted to the side.  The data from this period with S2 tilted was actually pretty good thanks to coordinate rotation but was not used.

S2 was mounted about 0.75m south of S1 at the same height and same north orientation, 17deg from true north.  The 20Hz data was processed using the flux processing code to do the coordinate rotations and calculate wind direction, 30min averages, variances and covariances.

Figure 1. Time series of Wind Direction and the rotation angles.

Figure 2. fig 2 Wind speed time series

Figure 3. Wind speed scatter

Figure 4. Rotated wind variance regressions

Figure 5. u-star and w't' time series

Figure 6. u-star and w't' regressions

Figure 7. Sonic temperature time series

Figure 8. Sonic temperature regression