35 holes were drilled through the ice in the smaller western lobe of Lake Bonney and the bathymetry of the lake was determined. A further 52 holes were used for the eastern lobe bathymetry. Sediment cores of up to 2m depth were obtained from the lake floor and analysed to determine the nature of the sediment cores and halite crystals recovered. The drill rig worked so well, it was transferred to ... Lake Vanda to obtain some cores from there to compliment previous cores which were not of the same quality. The expedition survey discovered and mapped the extent of the very large, pure, clear halite crystals occurring below 30m depth. Subsequent drilling resulted in cores having samples of dihydrohalite analysed by x-ray diffraction. A geomorphic investigation was made of the area extending from the Taylor Glacier snout down valley as far as the Naussbaum Reigel. As many as 23 former lake levels were identified. A small meltwater stream from the Calkin Glacier flowed overland until it reached a prominent kame terrace about 60m above Lake Bonney. The stream then disappeared into a cave some 15m long and 3m high. The stream was followed and studied to determine thermokarst processes, a term given when the melting of ground ice in unconsolidated sediments caused subsidence and pseudo-karst landforms like melt dolines, caves, natural bridges and subsurface flow. The overland flow and stream bifurcation of the Lake Bonney Reigel had the channel profiles surveyed in detail.
The data are provisional and subject to change as model improvements are implemented and new input data sets become available. Due to the fact that forcing data for Greenland are unreliable and the lack of a glacier/ice sheet model, snow water equivalent accumulates indefinitely in Greenland and a few other Arctic points. Therefore it is highly recommended that Greenland and other points with abnormally large snow water equivalent values be masked out when performing global analyses.
Goddard Earth Sciences Data and Information Services Center
NASA Goddard Space Flight Center
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Rodell, M., P. R. Houser, U. Jambor, J. Gottschalck, K. Mitchell, C.-J. Meng, K. Arsenault, B. Cosgrove, J. Radakovich, M. Bosilovich, J. K. Entin, J. P. Walker, D. Lohmann, and D. Toll, The Global Land Data Assimilation System, Bull. Amer. Meteor. Soc., 85(3): 381-394, 2004.