SWOT Observations Over Sea Ice: A First Look

Abstract We present a first examination of observations from the surface water and ocean topography (SWOT) mission over the polar oceans. In SWOT, bright, quasi‐specular leads are associated with lower heights relative to the surrounding ice cover. Surface heights and freeboard from SWOT and ICESat‐2 are compared in two near‐coincident segments in the Beaufort and the Weddell Seas. Correlations and mean differences between these 30‐km ICESat‐2 and SWOT height segments are 0.91 (−0.02 ± 0.08 m) in the Beaufort and 0.65 (0.01 ± 0.09 m) in the Weddell. Differences in freeboards using minimum height as a reference sea surface are 0.04 ± 0.08 m and −0.01 ± 0.09 m; minimum heights are localized within the same lead features of the two segments. The SWOT wide‐swath radar altimeter can, for the first time, provide two‐dimensional mappings of the spatial variability of freeboard and ice thickness — crucial information that will enhance our understanding of the physical mechanisms driving the decline of sea ice covers.