Algorithm to Eliminate the Wind Direction Ambiguity from the Monostatic High-Frequency Radar Backscatter Spectra

In this study, an algorithm is presented to eliminate the ambiguity of the wind direction from the monostatic radar. The true wind direction can be obtained by comparing three angles that reflect the differences between wind direction and three adjacent radar beams. The correlation coefficient and the root-mean-square (RMS) error between the inversion data and the anemometer data are 0.67 and 49.8 degrees, respectively. When the data whose wind speed is greater than the threshold 4.67 m/s are used, the correlation coefficient and the RMS error are 0.93 and 24.6 degrees. Therefore, the effect of the wind speed threshold on the radar measurements should be put into consideration in the data processing. The results make clear that the algorithm can remove the ambiguity of the wind direction effectively, and authors can utilise the algorithm to estimate the wind direction.