Deriving Antarctic Sea‐Ice Thickness From Satellite Altimetry and Estimating Consistency for NASA's ICESat/ICESat‐2 Missions

Abstract

AbstractWith the launch of the Ice, Cloud and Land Elevation Satellite‐2 (ICESat‐2), densely measuring the Antarctic ocean all year long, monthly sea ice thickness changes can be inspected. However, the consistency between ICESat‐2 and its predecessor ICESat remains unknown if a long‐term change of the Antarctic sea ice thickness is to be examined. Due to the complex physical structure of Antarctic sea ice, an improved One‐Layer Method (OLMi) for sea‐ice thickness retrieval, with an ∼0.3 m uncertainty, is proposed in this study. Using this method, the monthly sea ice variation in each sea sector of Antarctica from ICESat‐2 is inspected, revealing detailed characteristics of Antarctic sea ice over sector scale such as bi‐modal distributions. The different retrieving methods for the total freeboard from ICESat are found to be ∼0.036 m lower than that from ICESat‐2. The circum‐Antarctic sea ice thickness shows a decreasing tendency (2003–2020), especially in summer with −0.014 m/yr.