SGER Proposal: Iceberg drift in the near-shelf environment, Ross Ice Shelf, Antarctica

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0089902MacAyealThe recent calving of a large iceberg (B15) from the Ross Ice Shelf presents a unique opportunity to measure the processes which control the drift of large tabular icebergs including, wind-driven and thermohaline currents, tides, sea ice, and winds. The calving of such an extraordinarily large iceberg within the logistics reach of the US Antarctic Program, is rare. Thus the calving of B15 offers an exciting opportunity to study iceberg drift, and all of the other aspects of iceberg behavior which are associated with the long-term stability of the Antarctic environment.The extraordinary freshwater volume of large tabular icebergs has in the past been identified as a natural resource of human economic value (e.g., for water poor regions of the earth). Feasibility studies of iceberg towing to water-poor regions have largely been poo-pooed as science fiction. Nevertheless, tabular icebergs commonly travel thousands of miles as a result of natural processes which, if understood, could perhaps be harnessed for human economic and social value. We propose to make direct measurements of the drift of icebergs B15a, B15b and asmaller iceberg (either B16, B17 or B18, depending on circumstances) to:1. observationally constrain parameters that will improve the models of iceberg drift, e.g., by determining drag coefficients appropriate to atmospheric and oceanic interactions, including drag induced by sea ice,2. improve our ability to predict calving events and the subsequent iceberg drift trajectory,3. compliment ongoing remote sensing study of the iceberg and its behavior4. measure the progress of the berg(s) toward logistically sensitive areas.The last point reflects the fact that interest in B15's drift over the next year(s) is not restricted to the realm of basic science. It is conceivable that B15 and its progeny (it is now in two pieces and has caused smaller bergs to calve from the Ross Ice Shelf) poses a complication to normal shipping to and from the US's main research and logistics station in Antarctica. While this proposal represents the broad scientific interests of several investigators at several institutions, its focus is narrow. Support is requested for assembly and deployment of instruments to observe the weather conditions and the drift of B15.