This data set was acquired with a Kongsberg model EM120 multibeam sonar system during Nathaniel B. Palmer expedition NBP1005A conducted in 2010 (Chief Scientist: Dr. Patricia Yager). These data files include Sidescan, Acoustic Backscatter, Swath Bathymetry 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): ASPIRE (Amundsen Sea Polynya International Research Expedition), and funding was provided by the U.S. National Science Foundation.