EGU2020-20610
https://doi.org/10.5194/egusphere-egu2020-20610
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Sea ice characteristics during the Weddell Sea expedition explored by geophysical and remote sensing methods

Wolfgang Rack1, Frazer Christie2, Evelyn Dowdeswell2, Julian Dowdeswell2, Paul Wachter3, Toby Benham2, Christian Haas4, and Paul Bealing1
Wolfgang Rack et al.
  • 1Gateway Antarctica, University of Canterbury, Christchurch, New Zealand
  • 2Scott Polar Research Institute, University of Cambridge, Cambridge CB2 1ER, UK
  • 3DLR, Wessling, Germany
  • 4AWI, Bremerhaven, Germany

The 2019 Weddell Sea expedition provided a unique opportunity for geophysical and glaciological sea ice measurements in one of the least accessible regions of the Southern Ocean. Although the extent and area of sea ice is well known based on satellite measurements, the limited information on thickness does still hinder the calculation of trends trends in volume and mass. Sea ice thickness is therefore one of the missing key variables in the global cryosphere mass balance, and difficult logistics are a challenge for near synchronous satellite validation measurements. Another key variable in this context is snow on sea ice, as knowledge of snow is required to convert satellite-derived freeboard to thickness.

We measured the sea-ice morphology by a combination of on ice and remote sensing methods: near-synchronous temporal and spatial measurements from a drone equipped with a radar sensor and camera, manually-derived on-ice surveys and samples such as snow pits, snow-depth transects and drill holes, and a AUV with upward-looking multibeam sonars. We also deployed ice-drifter buoys on several ice floes which we used to provide floe drift over an extended period of time.

In this contribution we present the results of our observations in conjunction with a close sequence of high resolution satellite radar images (TerraSAR-X, Sentinel-1) and altimeter data (ICESat-2 and CryoSat-2) to characterise the sea ice conditions in the western Weddell Sea. We found a mixture of fragments of deformed first-year and multi-year sea-ice which was consolidated in larger ice floes. A thick snow cover frequently depressed the ice cover of the thinner first year ice below sea level. Satellite data allow to extend our findings in time to a larger area and to improve our information on sea ice over a larger region.

How to cite: Rack, W., Christie, F., Dowdeswell, E., Dowdeswell, J., Wachter, P., Benham, T., Haas, C., and Bealing, P.: Sea ice characteristics during the Weddell Sea expedition explored by geophysical and remote sensing methods, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20610, https://doi.org/10.5194/egusphere-egu2020-20610, 2020

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