Analysis of rain effects on wave height estimation from X-band nautical radar images

In this paper, the analysis of rain effects on wave height estimation from X-band nautical radar sea surface images is presented. A modified shadowing-analysis-based algorithm is applied to the radar data acquired in a sea trial in the North Atlantic Ocean under both rainy and rain-free conditions. The result shows that rain enhances the image pixel intensity and reduces shadowed areas, leading to the underestimation of wave heights. An increase of about 0.31 m in the bias with respect to in-situ measurements is found in the wave height retrieved from rain contaminated data compared to the results obtained from data without rain.