Investigating Coastal Polynya Thin Sea Ice State in the Laptev Sea Using TerraSAR-X Dual-Pol Stripmap Data
Thomas Busche(1), Thomas Krumpen(2), Lasse Rabenstein(2), Jens Hoelemann(3), Christian Haas(4), Irena Hajnsek(1) and Sascha Willmes(5)
(1) German Aerospace Center (DLR) e.V., Muenchner Str. 20, 82234 Wessling, Germany
(2) Alfred Wegener Institute, Bussestr. 24, 27570 Bremerhaven, Germany
(3) Alfred Wegener Institute, Columbusstrasse, 27570 Bremerhaven, Germany
(4) University of Alberta, 1-26 Earth Sciences Building, T6G 2E3 Edmonton (Alberta), Canada
(5) University of Trier, Behringstr. 21, 54286 Trier, Germany
The coastal areas of the Artic Basin are regions of new sea ice production and accumulation. The understanding of sea ice dynamics, besides its scientific impacts on climate modelling, may also evolve to a strategic meaning, as the coastal regions of the Artic -prospected to undergo an enormous change within a global warming scenario- may become accessible in terms of marine traffic and resource exploitation in the next decades.
Polarimetric SAR data is theoretically considered as a candidate for the retrieval of young, thin sea ice thickness from space. Some success is reported in the literature using dual and full polarimetric C-band and L-band data. A shorter wavelength is to be preferred due to its higher sensitivity to thin ice thickness. As a central motivation of this study it is of interest to test this hypothesis against polarimetric X-band data acquired by TerraSAR-X.
A ground and ship based measurements campaign in the Laptev-Sea took place in April/May2008 during the Russian-German Transdrift XIII expedition, organized by the Arctic and Antarctic Research Institute (AARI), St Petersburg, Russia, the GEOMAR Institute, Kiel, and the Alfred Wegener Institute (AWI) for Polar and Marine Research, Bremerhaven, and the University of Trier, all three located in Germany, together with other Russian partner institutes. One of the objectives of Transdrift XIII was to collect data to validate and to refine results from polynya numeric modelling efforts. High resolution Helicopter borne profiling flights, involving electromagnetic induction techniques, using AWIs EM-Bird Sensor, have been conducted to investigate the actual state and thickness of the thin-ice zone. Coincident to the helicopter profiling flights spaceborne C-band SAR data from the ENVISAT-ASAR sensor in wide swath mode and X-band TerraSAR-X data in dual polarisation strip map mode, as well as optical data from the MODIS sensor, have been successfully acquired. In the following study, presented here, first results from the comparison of the TerraSAR-X data with the EM-Bird profiles towards thin ice thickness measurements are presented.