Abstract
In this paper, the retrieving significant wave height from X-band marine radar images based on shadow statistics is investigated, since the retrieving accuracy can not be seriously affected by environmental factors and the method has the advantage of without any external reference to calibrate. However, the accuracy of the significant wave height estimated from the radar image acquired at the near-shore area is not ideal. To solve this problem, the effect of water depth is considered in the theoretical derivation of estimated wave height based on the sea surface slope. And then, an improved retrieving algorithm which is suitable for both in deep water area and shallow water area is developed. In addition, the radar data are sparsely processed in advance in order to achieve high quality edge image for the requirement of shadow statistic algorithm, since the high resolution radar images will lead to angle-blurred for the image edge detection and time-consuming in the estimation of sea surface slope. The data acquired from Pingtan Test Base in Fujian Province were used to verify the effectiveness of the proposed algorithm. The experimental results demonstrate that the improved method which takes into account the water depth is more efficient and effective and has better performance for retrieving significant wave height in the shallow water area, compared to the in situ buoy data as the ground truth and that of the existing shadow statistic method.
Highlights
As is well known, ocean wave is one of the most common ocean fluctuation phenomena
We carry out retrieving the significant wave height based on the collected radar images at a near-shore area to examine the validity of our proposed method
Since the radar echo intensity is saturated and the radar echo are mainly affected by the tilt modulation in the near segment of the radar image, the selected area is at least 400 m from the radar platform
Summary
Ocean wave is one of the most common ocean fluctuation phenomena. It is vitally important to understand the waves and their associated characteristics for ocean research and ocean exploitation [1,2,3,4]. According to the characteristic that the shadowing in the radar image changes with the distance from radar antenna to the sea surface, the method to estimate the significant wave height by using the visualization function was proposed in [28]. The feasibility of this method was proved by the simulated radar image. Our primary goal is to propose an improved algorithm, which is more suitable for estimating wave height both in the shallow water and deep water areas, based on the shadow statistics to efficiently and effectively retrieve the significant wave height. Notation: Scalars, vectors and matrices are expressed by regular, bold lowercase letters and bold uppercase letters, respectively
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
