Circum-Antarctic sea-ice lead frequencies and regional characteristics from satellite imagery
Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
Final Report Abstract
Based on the project, a novel observational lead data set in the Antarctic was derived. Therefore, we have adjusted the existing Arctic lead retrieval algorithm and implemented major improvements. A two‐level processing is used to identify potential sea ice leads in individual MODIS tiles, from which cloud artefacts are subsequently separated from true lead observations. Furthermore, a retrieval uncertainty is calculated providing detailed information on the reliability of the data product on a pixel‐basis. The dataset covers the winter months April to September 2003 to 2019 and the algorithm allows an operational and continuous identification of daily sea ice leads. Long‐term and monthly averaged maps of lead frequencies are derived and analyzed. In the long‐term average, we identified several hot‐spot regions in the Southern Ocean, where sea ice leads occur more frequently compared to other areas. These are the coastline, the continental shelf break, and several features in the deep sea. Particularly the continental shelf break is interesting and results from a regional model configuration of the ice‐ocean model NEMO‐LIM 3.6 are used to identify certain regions of increased divergence. Monthly averages suggest that the variability and frequency decreases towards September in several hot‐spot regions. However, further analysis and additional data are needed to investigate the impact of external forcing. Particularly results from ocean models are needed at comparable high spatial resolution to relate the results to the lead observations.
Publications
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2018 Ship‐based wind lidar measurements of the Antarctic boundary layer (SWIANT). In: The Expedition PS111 of the Research POLARSTERN to the southern Weddell Sea in 2018 (ed. M. Schröder). Reports on polar and marine research, Bremerhaven, Alfred Wegener Institute for Polar and Marine Research 718, 161pp
Reiser, F., Schnaase, F., Heinemann, G.
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2019: A satellite‐based climatology of wind‐induced surface temperature anomalies for the Antarctic. Remote Sens. 11, 1539, 17pp
Heinemann, G., Glaw, L., Willmes, S.
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2019: Predominant sea‐ice fracture zones around Antarctica and their relation to bathymetric features. Geophysical Research Letters, 46, 12117– 12124
Reiser, F.; Willmes, S.; Hausmann, U.; Heinemann, G.
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2020: A New Algorithm for Daily Sea Ice Lead Identification in the Arctic and Antarctic Winter from Thermal‐Infrared Satellite Imagery. Remote Sens., 12, 1957
Reiser, F.; Willmes, S.; Heinemann, G.
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2020: Unmanned Aerial Systems for Investigating the Polar Atmospheric Boundary Layer— Technical Challenges and Examples of Applications. Atmosphere, 11(4), 41
Lampert, A.; Altstädter, B.; Bärfuss, K.; Bretschneider, L.; Sandgaard, J.; Michaelis, J.; Lobitz, L.; Asmussen, M.; Damm, E.; Käthner, R.; Krüger, T.; Lüpkes, C.; Nowak, S.; Peuker, A.; Rausch, T.; Reiser, F.; Scholtz, A.; Sotomayor Zakharov, D.; Gaus, D.; Bansmer, S.; Wehner, B.; Pätzold, F.
