Sea level maps over Polar Regions derived from Satellite Altimetry

Over the Arctic and Southern Oceans, the presence of sea ice prevents the use of satellite altimetry to obtain reliable sea level observations. However, recent developments in data processing now allow us to obtain sea level estimates over the zones where the sea ice is fractured (sea ice leads), thus making possible the production of sea level maps over polar regions, including ice-covered zones.

Sea level maps over the Arctic and Southern Oceans were produced over the period 01-2011 to 01-2024 by combining observations from 3 missions from 50°N/S to 88°N/S, using an optimal interpolation algorithm. Three satellite missions (Sentinel-3A, SARAL/AltiKa and Cryosat-2) are processed using the same altimetric standards and the resulting sea level observations are in good agreement. The products are distributed on the Aviso Regional Products portal and constitute a demonstration dataset prior to the next-generation of operational CMEMS-SLTAC products. The sea level maps are validated against hourly Gloss/CLIVAR tide gauge and bottom pressure recorders at the north pole and in the Beaufort Sea (BGEP project) showing a good correlation at seasonal timescales. Polar sea level trends are also estimated over the full 12 years period, providing insight over annual to decadal sea level variability.

Future product evolutions might include discarding the melt ponds observations during summer and the calibration of the polar products against the products derived for the global ocean. Extending the product time-series length using historical ENVISAT observations is also planned for the near future.