Assessing the impact of geometric sampling differences on Arctic sea ice thickness from Envisat and CryoSat-2
Abstract
Multi-decadal observations of sea ice thickness, in addition to those available for extent, are key to understanding long-term changes in Arctic sea ice. The European Space Agency's (ESA) ERS-1, ERS-2, Envisat and CryoSat-2 satellite radar altimeter missions provide a continuous 25-year (1993-present) dataset with the potential to estimate Arctic sea ice thickness up to 81.5°N. However, differences in the satellite footprints will cause discrepancies in their surface type discrimination. Here we focus on the impact of geometric sampling differences between Envisat and CryoSat-2 by assessing their lead densities and sea ice floe size and thickness distributions during the mission overlap period of November 2010-March 2012. We find that Envisat preferentially samples wider, thicker sea ice floes leading to a thickness bias between Envisat and CryoSat-2 of 77 cm over first year ice and 22 cm over multiyear ice. By applying an Envisat thickness correction that is dependent on floe size distribution we provide a new, physically-based approach to addressing the bias between the satellites. The correction will enable us to produce a 15-year time series of Arctic sea ice thickness in the seasonal ice zone, up to the Envisat limit of 81.5°N. There is the potential to extend such a bias correction method to past missions such as ERS-1 and -2, the current Sentinel-3 mission, and future satellite radar altimeters.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C21A..06T
- Keywords:
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- 0726 Ice sheets;
- CRYOSPHEREDE: 0728 Ice shelves;
- CRYOSPHEREDE: 0750 Sea ice;
- CRYOSPHEREDE: 0758 Remote sensing;
- CRYOSPHERE