Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica
Landfast sea ice (fast ice) attached to the Antarctic coast is a critical element of the local physical and ecological systems. Through its direct coupling with the atmosphere and ocean, fast ice and its snow cover are also a potential indicator of processes related to climate change. However, in-si...
| Main Authors: | , , , |
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| Format: | Conference Object |
| Language: | unknown |
| Published: |
2019
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| Subjects: | |
| Online Access: | https://epic.awi.de/id/eprint/52680/ https://hdl.handle.net/10013/epic.3a9f3481-3a35-441a-bbe7-a0864c3d9a78 |
| Summary: | Landfast sea ice (fast ice) attached to the Antarctic coast is a critical element of the local physical and ecological systems. Through its direct coupling with the atmosphere and ocean, fast ice and its snow cover are also a potential indicator of processes related to climate change. However, in-situ fast-ice observations in Antarctica are extremely sparse because of logistical challenges. Since 2010, a monitoring program, which is part of the Antarctic Fast Ice Network (AFIN), has been conducted on the seasonal evolution of fast ice of Atka Bay. The bay is located on the north-eastern edge of Ekström Ice Shelf in the eastern Weddell Sea, close to the German wintering station Neumayer III. A number of sampling sites have been regularly revisited between annual ice formation and breakup each year to obtain a continuous record of snow depth, freeboard, sea-ice- and sub-ice platelet layer thickness across the bay. Here, we show the results of these measurements, combining them with observations from the nearby meteorological observatory at Neumayer Station as well as satellite images to relate the seasonal and interannual fast-ice cycle to the factors that influence its evolution. On average, the annual fast-ice thickness at the end of the growth season is about 2 meters, with a platelet layer accumulation of 4 meters beneath. Due to the substantial snow accumulation on the ice, a characteristic feature is frequent negative freeboard and associated flooding of the snow/ice interface. Results highlight the predominately seasonal character of the fast-ice regime in Atka Bay without a significant trend in any of the observed variables over the 9-year observation period. Also, no changes are evident when comparing with measurements in the 1980s and 1990s. However, strong easterly winds in the area govern the year-round snow redistribution and also trigger the breakup events of the bay during summer months. An enhanced knowledge on the seasonal and interannual variability of fast ice in this region will improve our understanding on local atmosphere/sea ice/ocean interactions which can then be transferred to pan-Antarctic fast-ice regimes. |
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