Seafloor Topography Recovery Using the Observation Data of Tiangong-2 Interferometric Imaging Radar Altimeter

Abstract

Tens of years of altimetry sea surface height (SSH) data has continuously contributed to the development of global seafloor topography models because it can be used to precisely retrieve the gravity variation caused by seafloor topography. The development and application of altimeter has come to a new era from conventional nadir-looking altimeters to interferometric wide-swath altimeters as the successful launch of the Interferometric Imaging Radar Altimeter on board Chinese Tiangong 2 space laboratory (TG2 InIRA). Compared with conventional altimeters, the observation efficiency of TG2 InIRA has been greatly improved. This paper presents for the first time the results of seafloor topography derived from TG2 InIRA data in west Pacific Ocean and South China Sea regions. The root mean squared errors (RMSE) of the recovered topographies by gravity-geologic method (GGM) referring to the shipborne measurements in these two regions are 69.882 and 50.110 m, respectively. The recovered topographies are also evaluated by comparing with five well-known topography models. Furthermore, two subareas in west Pacific Ocean region are selected to conduct a supplemental experiment showing that more revisits can help achieve better recovery. The RMSE of the more revisited subarea is 66.808 m, while the RMSE of the less revisited subarea is 79.273 m.