Processed bathymetry data (netCDF grid format) of selected seamounts along the Southwest Indian Ridge, James Cook cruise JC066, 2011

The JC066 swath bathymetry data was acquired with a hull-mounted Kongsberg-Simrad EM120 multibeam echo sounder in 2011 during James Cook cruise JC066 (chief scientist Alex David Rogers). The bathymetry survey focussed on a number of seamounts along the Southwest Indian Ridge and was designed to minimise shadow zones over the summits and to reduce the effects of bubble entrainment, However, adverse weather conditions resulted in poor-quality backscatter for two sites, Coral and Melville. Shipboard editing of acquired data was conducted in CARIS HIPS and SIPS, incorporating navigation and sound velocity corrections. The .all files are available from the British Oceanographic Data Centre (BODC), and further manual processing was conducted in Qimera 2.3.1 and Mb System (swath bathymetry) and FMGeocoderToolbox (FMGT) 7.9.5 (backscatter) to remove erroneous data points. Backscatter data for the Coral and Melville sites was subsequently filtered in QGIS 3.12 to reduce the strength of data artefacts. The grids were generated at a horizontal resolution of 25m and cover the areas of Atlantis bank, Coral seamount, Melville seamount, Sapmar seamount and "Middle of What" seamount. The files are in GMT-compatible netCDF grid format. Funding for the work was provided through a UK-NERC grant.