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UP: Fachverband Umweltphysik

UP 7: Cryosphere, Hydrosphere and Oceanography

UP 7.1: Hauptvortrag

Mittwoch, 28. März 2012, 15:00–15:30, HFT-FT 131

Uncertainties of sea ice thickness estimates from SMOS radiometry and CryoSat-2 synthetic aperture radar altimetry — •Lars Kaleschke, Nina Maaß, and Xiangshan Tian-Kunze — Institut für Meereskunde, KlimaCampus, Universität Hamburg

Sea ice plays an important role in the climate system. Firstly, it is considered as an early indicator of climate change because of the amplification of climatic variations in the polar regions. Secondly, sea ice is involved in the processes that drive the polar amplification and has a potential global impact on climate. The uncertainties of sea ice thickness estimates are of particular relevance for analysing the reliability of climate models.

Data from the recently launched ESA satellites CryoSat-2 and SMOS can be used to estimate sea ice thickness. Although both sensors take advantage of a synthetic aperture principle, they do provide complementary information. CryoSat-2 measures the elevation of the sea ice surface, the so-called freeboard, with an active radar system. The sea ice thickness can be inferred from the freeboard with several assumptions, e.g. about sea ice density and the backscatter horizon within the snow surface. SMOS measures the thermal radiation at a wavelength of 21 cm. Electromagnetic radiation with this long wavelength emerges from the ice-ocean interface and can be used to infer the sea ice thickness with assumptions about the ice temperature and salinity that affect the penetration depth and emissivity. In this presentation we will give an overview of the methods and the associated uncertainties for deriving sea ice thickness from SMOS and CryoSat-2.