Quantification of sea ice production in the southern Weddell Sea using a synergy of numerical simulations and remote sensing data
Oceanography
Final Report Abstract
In this project we have combined model results and observational data to quantify sea-ice production for the southwestern Weddell Sea. Sea-ice production in this region is concentrated in polynyas along the coast and the ice shelf front. A multi-method approach is used to quantify sea-ice production in polynyas in the southern Weddell Sea for the period 2002-2014. We use 1) a high-resolution regional climate model, 2) sea-ice retrievals from optical satellite data, and 3) simulations of a sea-ice/ocean model. Methods 2) and 3) need atmospheric forcing, which is taken from different reanalyses as well as from a regional climate model of the project. We identified uncertainties in both observational data and model results. Specifically, inconsistencies between the locations of coastlines, ice shelf front, and fast-ice areas were found to lead to substantial bias both in modelled and in remote-sensing data. Data assimilation using information about areas of landfast ice and grounded icebergs improved modelled freezing rates considerably. We developed strategies to combine the different data sets in a consistent way and came to robust conclusions about sea-ice formation in the different sectors of the Weddell Sea and its variability. The results of the project are important for the understanding of the driving mechanisms for water mass modification and ocean circulation, which play a crucial role in determining the rate of melting the ice shelf base. This is of relevance also for the discharge of solid ice from the Antarctic continent – which in turn contributes to global sea level change. G. Heinemann, Trierischer Volksfreund 12.3.16: „Sommer bei minus 17 Grad Celsius - Trierer Forscher untersuchen die Atmosphäre in der Antarktis“ G. Heinemann: live interview SWR-Landesschau 31.3.16 G. Heinemann: interview Sat1 22.6.16. http://www.1730live.de/forschung-im-ewigen-eis/ G. Heinemann: interview SWR 7.3.18, https://www.swr.de/swraktuell/rp/trierer-ausstellung-eiskalte-forschung-auf-spurensuche-im-ewigen-eis/- /id=1682/did=21441934/nid=1682/akszx2/index.html G. Heinemann: interview NDR 26.3.18, https://www.ndr.de/fernsehen/sendungen/nordmagazin/Rostock-Treffen-der-Polar-und-Klimaforscher,nordmagazin50234.html
Publications
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2016: Meteorology and oceanography of the Atlantic sector of the Southern Ocean - a review of German achievements from the last decade. Ocean Dynamics 66, 1379 – 1414
Hellmer, Hartmut H.; Rhein, Monika; Heinemann, Günther; Abalichin, Janna; Abouchami, Wafa; Baars, Oliver; Cubasch, Ulrich; Dethloff, Klaus; Ebner, Lars; Fahrbach, Eberhard; Frank, Martin; Gollan, Gereon; Greatbatch, Richard J.; Grieger, Jens; Gryanik, Vladimir M.; Gryschka, Micha; Hauck, Judith; Hoppema, Mario; Huhn, Oliver; ... & Wolf-Gladrow, Dieter
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2016: Observations of the hydrographic conditions and water mass compositions at the Filchner Sill and in the Filchner Trough. In: The Expedition PS96 of the Research Vessel POLARSTERN to the southern Weddell Sea in 2015/2016 (ed. M. Schröder). Reports on Polar and Marine Research 700, Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany, 148pp
Schröder, M., A. Wisotzki, R. Timmermann, L. Stulic, S. Ryan, J. Geilen, M. Rankl, J. Christmann, S. Østerhus
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2018: Analysis of the performance of a ship-borne scanning wind lidar in the Arctic and Antarctic. Atmos. Meas. Tech. Discuss.
Zentek, Rolf; Kohnemann, Svenja H. E. & Heinemann, Günther
