This study concerns the formation processes of Weddell Sea Bottom Water, a very cold and saline water mass found at the continental shelf edge of the southernmost Weddell Sea. The formation process is believed to involve saline but warm Circumpolar Deep Water, and extremely cold but relatively fresh Ice Shelf Water, however little is known about the process itself. Weddell Sea Bottom Water is important since it is a precursor to Antarctic Bottom Water, a dense, globally distributed water mass. The outflow of Ice Shelf Water from beneath the Filchner-Ronne Ice Shelf has been the subject of a continuing international field program. In February and March of 1998, a British Antarctic Survey (BAS) cruise on board H.M.S. Endurance will focus on the oceanic and atmospheric exchange processes within the open water at the face of the ice shelf. This study is an integral part of the scientific program of the cruise and will concern the mechanisms responsible for the mixing of Ice Shelf Water with other regional water masses as it emerges from under the ice shelf. The measurements that will form the basis for the analysis include vertical profiles of temperature, conductivity, and velocity microstructure; acoustic Doppler current profiles, and rapidly-sampling temperature sensors mounted on BAS current meter moorings. Data sets collected by other participants in the cruise will include atmospheric measurements, a regional survey of the hydrographic structure of the upper ocean, and satellite-based remote sensing products.
