Sonic 6u appears to have an offset in the u component (from the mean of all 9 upwind sonics) of about +15 cm/s. However the range of u and v offsets (from the mean) for all 9 sonics is about +/- 20 cm/s. 6u stands out because there is no other sonic with a positive offset this large, while there are a couple of sonics with a u component offset near -20 cm/s.