Transforming coastal mapping from space

Abstract

Global marine gravity fields—variations in Earth’s gravitational pull across the ocean surface—provide valuable information about seafloor topography and plate tectonics beneath the water, knowledge that is essential for understanding geological features and ocean dynamics. A technique that estimates Earth’s surface heights from space, called satellite altimetry, has partially resolved marine gravity fields (1, 2). However, conventional altimetry can only obtain one-dimensional measurements along a satellite track. The 2022 Surface Water and Ocean Topography (SWOT) mission marked a considerable advancement in satellite altimetry because it captures two-dimensional, large-area topography data with high precision (3). On page 1251 of this issue, Yu et al. (4) report that a gravity field derived from 1 year of SWOT data reveals plate tectonics along the deep ocean floor that had remained hidden for the past 30 years with conventional altimeter observations. This level of detail could improve understanding of ocean environment and dynamics.