Drift-aware sea ice thickness maps from satellite remote sensing

Abstract

The standard approach to deriving gridded sea ice thickness (SIT) from satellite altimeters is to aggregate the original along-track SIT estimates over a 1-month period to achieve sufficient coverage across the Arctic. However, this approach neglects processes like sea ice advection, deformation, and thermodynamic growth that occur within the aggregation period. To address these limitations, we propose a drift-aware method that accounts for sea ice motion and SIT changes due to dynamics and thermodynamics in monthly SIT products. We present a method to derive daily drift-aware sea ice thickness (DA-SIT) maps for the Arctic based on Envisat and CryoSat-2 along-track data. The approach is validated against buoys, airborne SIT surveys, and moored upward-looking sonar (ULS) measurements. DA-SIT demonstrates the ability to register sea ice thickness anomalies, which are also observed by daily ULS SIT averages but are overlooked by the conventional gridded SIT data. Comparative analysis reveals that drift awareness reduces orbit track patterns in the gridded SIT and improves consistency in regions with significant ice drift, such as the transpolar drift. The drift awareness facilitates detailed studies of regional sea ice dynamics and fluxes, while improving co-registration of multi-mission satellite data. However, when considering pan-Arctic estimates of ice volume, we do not expect significant changes in time series and trends compared to in existing studies.