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UP: Fachverband Umweltphysik
UP 3: Kryosphäre
UP 3.9: Talk
Tuesday, March 14, 2017, 14:45–15:00, GW2 B3009
Microwave emission from growing sea ice at L-band: a modeling study — •Marcus Huntemann1,2 and Georg Heygster2 — 1Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany — 2University of Bremen, Bremen, Germany
Satellite based microwave observations of sea ice are taken continuously since the late 70s while even lower frequencies like L-band became available just recently with SMOS (2010), Aquarius (2012) and SMAP (2015). At L-band the penetration depth into sea ice is deeper compared to the higher frequencies and many studies found a relation with the actual ice thickness up to about 50 cm. We simulated many cases of the sea ice evolution using a thermodynamic ice growth and snow accumulation model driven by atmospheric reanalysis data. The resulting profiles of sea ice and snow parameters are used as input for a microwave emission model to model the emitted radiation. This large database of sea ice conditions and corresponding simulations of emitted radiation serves to analyze the sensitivity of the emitted radiation to variation in the geophysical parameters. We find correlations with physical parameters like ice thickness, temperature and salinity, as well as snow densification and thickness. Using specialized models, we additionally quantify the influence of coherence effects originating from thin snow cover and the roughness of the sea ice top and bottom interfaces. Most of these parameters are simplified or unconsidered in current emissivity models and retrievals of ice thickness from L-band satellite observations.