Preliminary Significant Wave Height Retrieval from Interferometric Imaging Radar Altimeter Aboard the Chinese Tiangong-2 Space Laboratory

The interferometric imaging radar altimeter (InIRA) aboard the Chinese Tiangong-2 space laboratory is first spaceborne working at low incidence angles. This study focuses on retrieval of significant wave heights (SWHs) from InIRA data. retrieved SWHs can be used for correcting sea state bias InIRA-derived surface and supplement SWH products other sensors. First, we analyzed tilt, range bunching velocity modulations angles, found clear dependencies between two defined factors, azimuth integration, ocean waves in directions, respectively. These were further confirmed using measurements collocated WaveWatch III (WW3) Then, an empirical orthogonal model integration factors as inputs was proposed. segmented by angle, coefficients estimated fitting collocation each angle bin. Finally, data proposed model. retrievals validated both WW3 (JASON2, JASON3, SARAL, HY2A) SWHs. validation with shows a root mean square error (RMSE) 0.43 m, while average RMSE all traditional 0.48 m. indicates that to measure