Advance in Sea Surface Wind and Wave Retrieval from Synthetic Aperture Radar Image: An Overview

Synthetic aperture radar (SAR) aboard SEASAT was first launched in 1978. At the beginning of the 21st century, the Chinese remote sensing community recognized the urgent need to develop domestic SAR capabilities. Unlike scatterometers and altimeters, space-borne SAR offers high-resolution images of the ocean, regardless of weather conditions or time of day. SAR imagery provides rich information about the sea surface, capturing complicated dynamic processes in the upper layers of the ocean, particularly in relation to tropical cyclones. Over the past four decades, the advantages of SAR have been increasingly recognized, leading to notable marine applications, especially in the development of algorithms for retrieving wind and wave data from SAR images. This study reviews the history, progress, and future outlook of SAR-based monitoring of sea surface wind and waves. In particular, the applicability of various SAR wind and wave algorithms is systematically investigated, with a particular focus on their performance under extreme sea conditions.