This data set was acquired with a SeaBeam Instruments model 2112 multibeam sonar system during Nathaniel B. Palmer expedition NBP9903 conducted in 1999 (Chief Scientist: Dr. Eugene Domack). These data files include Swath Bathymetry, Acoustic Backscatter data and were processed at sea using the open source MB-System multibeam sonar processing software. Data were acquired as part of the project(s): Palmer Deep, Andvord Bay and Lallemand Fjord Geology and Geophysics Studies, and funding was provided by the U.S. National Science Foundation.