Measurement errors and correction of the UAT-2 ultrasonic anemometer

Two kinds of measurement errors have been observed in the recently developed UAT-2 ultrasonic anemometer. One is the flow distortion produced by a “blocking effect”, and the other is the angle of attack caused by the vertical misalignment of the instrument. Here, we study these errors and discuss the possible correction methods. Via a wind tunnel experiment and numerical simulation, a 3D calibration matrix was developed to correct the “blocking effect”. In the field test, the angle of attack was detected by an inclinometer settled on the reference plane of the anemometer, and the instrumental misalignment or tilt was corrected by a coordinate transformation. The combined use of an inclinometer and the proposed correction method may help find a new approach for vertical velocity correction.