An Algorithm for Wind Direction Retrieval From X-Band Marine Radar Images

A new method for retrieving wind direction from X-band marine radar images is presented in this letter. The new algorithm investigates radar backscatter in the wavenumber domain and obtains wind direction from the wavenumber spectrum. Different from previous algorithms that detect rain-contaminated images and discard them, the new algorithm could be applied to both rain-contaminated and rain-free images. For rain-contaminated images collected under low wind speeds (i.e., less than 8 m/s), wind directions were retrieved based on spectral components with wavenumbers of [0.01, 0.2]. For rain-contaminated images obtained under high wind speeds and rain-free images, wind directions were retrieved from the spectrum with values at zero wavenumber. The algorithm has been tested using X-band radar images and shipborne anemometer data collected on the east coast of Canada. Comparison with the anemometer data shows that the root-mean-square error of wind directions retrieved from rain-contaminated images collected under low wind speeds is reduced by 25.1°.