DOI: 10.5285/f2dfeda9-bf44-4ef5-89a3-ee5e434a385c
title: A multibeam-bathymetric compilation for the southern Amundsen Sea shelf, 1999-2019

description: We present a new compilation of multibeam-bathymetric data for the inner Amundsen Sea continental shelf beyond Thwaites and Pine Island glaciers (bounding box: 100W to 110W, 74S to 75.5S). The region includes Pine Island Bay, marine areas offshore the Thwaites Ice Shelf to the Crosson Ice Shelf, and covers an area of 74,750 km2. The bathymetric grids were compiled from all available multibeam echosounder (MBES) data acquired by UK, German, USA and Korean scientific cruises to the area between 1999 and 2019 (see lineage). Three grids of sea floor elevation data are available in a range of formats (ESRI ascii interchange format and GMT-compatible netCDF 4byte float): a 50-m resolution grid with no interpolation, a 50-m grid interpolated up to 300 m from cells with real data, and a 500-m resolution grid with no interpolation. Note that these grids have not been merged with regional bathymetric grids and, therefore, do not have continuous coverage (i.e. cells are only populated where multibeam data exist). This work was supported by grants from the National Science Foundation (NSF: Grant OPP- 1738942) and Natural Environment Research Council (NERC: Grant NE/S006664/1) as part of the International Thwaites Glacier Collaboration (ITGC) programme, and grants NE/J005770/1 and NE/J005703/1 as part of the iSTAR Programme.
description: The multibeam-bathymetric grids were compiled from a variety of data sources. Multibeam echosounder (MBES) data used are from 12 scientific cruises undertaken by British Antarctic Survey (BAS), Alfred Wegener Institute (AWI), California Institute of Technology (Caltech), Stanford University, University of East Anglia, Lamont-Doherty Earth Observatory of Columbia University, the Korean Polar Research Institute (KOPRI), and Rice University. The complete list of cruises can be found as Table 1 in the reference paper (Hogan et al., 2020). MBES sounding data were cleaned during each cruise and then collated and gridded using the 'mbgrid' program of MB-System. The grid was produced using the following mbgrid command parameters from MB-system version 5.6002: "-R-110/-100/-75.5/-74 -E50/50! -F1 -Jepsg3031 -A2 -C0 -V". This uses a Gaussian weighted mean filter algorithm. Additional parameter -G4 used to create ESRI-format ascii grids. Additional obvious outliers were removed from the individual sounding datasets at this stage and the data were re-gridded. This iterative process was repeated until a clean combined dataset was produced. For the interpolated 50-m grid, a small amount of interpolation was applied to fill data gaps up to 300 m away from cells with real sounding data in the "southASE_mbes_50m_interp.asc"; grid using the parameter -C3/1. Here, values are interpolated up to three grid cells from the nearest data point only if additional data are found in two opposite directions. Grids created in projection WGS84 Antarctic Polar Stereographic (epsg: 3031) The complete list of the cruises used for the compilation is described below * RRS James Clark Ross expeditions: JR179 (Larter, R.D , Hillenbrand, C-.D. , Graham, A.C.G., Smith, J.A.), JR294 (Abrahamsen, E.P., Heywood, K.A.) * RV Nathaniel B. Palmer cruises: NBP99-02 (Anderson, J.B, Wellner, J.S.), NBP07-02 (Nitsche, F.O.), NBP09-01 (Nitsche, F.O), NBP19-01 (Thompson, A., Dunbar, R.), NBP19-02 (Hogan, K.A, Larter, R.D, Graham, A.C.G, Kirkham, J.D., Totten Minzoni, R, Clark, R., Fitzgerald, V.), * RV Araon cruise: ANA02C (Hong, J.) * RV Polarstern cruises: PS104 (Gohl, K.Hillenbrand, C-.D., Larter, R.D., Arndt, J.E., Gohl, K.), ANTXXIII/4 (Hillenbrand, C-.D., Gohl, K.) , ANTXXVI/3 (Hillenbrand, C-.D., Gohl, K.)
description: Please refer to the literature reference (https://doi.org/10.5194/tc-2020-25) for full details on the instrumentation and data sources of the contributing datasets.
description: Quality control was undertaken manually to remove any outliers in the source datasets. This involved cleaning of the raw data during or after each individual cruise, and then again after compiling the datasets. For cruise NBP19-02, one of the principal datasets in the grid, the raw data cleaning was done using the "mbedit" and "mbeditviz" programs from MB-system. Other BAS datasets were also cleaned using "mbedit".