The Influence of Platelet Ice and Snow on Antarctic Landfast Sea Ice

• Main Authors: Hoppmann, Mario, Nicolaus, Marcel
• Format: Conference Object
• Language: unknown
• Published: 2012
• Subjects: Antarc*; Antarctic; Ice Shelves; Iceberg*; Sea ice
• Online Access: https://epic.awi.de/id/eprint/30670/; https://epic.awi.de/id/eprint/30670/1/Phd%20Days%202012.pdf; https://hdl.handle.net/10013/epic.39630; https://hdl.handle.net/10013/epic.39630.d001

Sea ice fastened to coasts, icebergs and ice shelves is of crucial importance for climate- and ecosystems. Near Antarctic ice shelves, this land-fast sea ice exhibits two unique characteristics: a significant fraction of incorporated ice platelets and a thick snow cover, leading to surface flooding and snow-ice formation. In order to investigate the spatial and temporal variability of sea-ice and snow thicknesses, we have initiated a regular observation program on the land-fast sea ice of Atka Bay as part of the international Antarctic Fast Ice Network (AFIN). Here we describe our monitoring activities and present first results of 2010 and 2011. Manual thickness measurements were performed at 6 locations along an east-west profile, every 3 weeks from June to December 2010 and from May 2011 to January 2012. Starting in November 2011, over 200 km of high-resolution, electromagnetic (EM31) thickness data were acquired. A mass balance buoy frozen into the sea-ice since August 2011 provides time-series of thickness data of high temporal resolution and allows us to investigate thermodynamic properties of sea ice and its snow cover. At the same time, an automatic weather station was deployed on the land-fast sea ice to provide model forcing data. First results show high variability in snow and sea-ice thicknesses over the entire Bay. In the East, a thick snow cover leads to extensive surface flooding. In the West, dynamic conditions lead to high sea-ice thickness. Ice platelets were observed regularly in the boreholes. Upcoming texture analysis of ice-cores taken at each of the stations at the end of the respective growth season will reveal the contribution of incorporated platelet ice and snow ice to the total sea-ice thickness. During our field campaign in November 2012, the monitoring will be extended by under-ice CTD profiles, a portable under-ice camera system and a radiation station.