Performance of Tiangong-2 Interferometric Imaging Radar Altimeter on Marine Gravity Recovery Over the South China Sea

In this article, the results of marine gravity recovery over the South China Sea are reported by using the sea surface height (SSH) data measured by Tiangong-2 interferometric imaging radar altimeter (TG2 InIRA). The high observation efficiency is demonstrated even only single swath is observed. The derived gravity anomalies by TG2 InIRA and by conventional altimeters (CAs) [Jason-2 (J2) and SARAL (SA)] are compared with the published gravity models and shipborne gravity measurements, showing that the accuracy of TG2 InIRA is a little better than that of CAs, although the signal bandwidth of which is only 40 MHz. Besides, the comparisons of the residual gravity anomalies also exhibit finer textural information and higher spatial resolution of TG2 InIRA. More interestingly, the potential for the coastal gravity recovery by TG2 InIRA is presented, although the land influence exists when the track is orthogonal to the coast and when the track is parallel to the coast. The achieved results of TG2 InIRA make us believe that more powerful wide-swath altimeters, e.g., the Surface Water and Ocean Topography (SWOT) mission, can bring a revolutionary contribution to the survey of marine gravity field in the future especially for the coastal areas.