Quality Assessment of GEBCO 08, Smith and Sandwell and SRTM30 Plus Grids in the Arctic

• Main Authors: Abramova, Anastasia, Monahan, Dave, Mayer, Larry A., Lippmann, Thomas C., Calder, Brian R.
• Format: Text
• Language: unknown
• Published: University of New Hampshire Scholars' Repository 2012
• Subjects: Oceanography and Atmospheric Sciences and Meteorology; Arctic
• Online Access: https://scholars.unh.edu/ccom/679; http://abstractsearch.agu.org/meetings/2012/FM/OS51D-1905.html

Several global compilations of gridded bathymetric data are available to the scientific community often leaving users wondering which data set is best for a given application. The choice of a bathymetry grid is complicated by the fact that there is little supplementary information provided on the accuracy and quality of the gridded products. The IBCAO grid is considered to be the most authoritative representation of Arctic bathymetry, even though in some areas it is based on digitized contours from published maps. Recently Smith and Sandwell (S&S) extended their bathymetric model based on acoustic soundings combined with gravity data as far as 81°N, presenting an alternative to the IBCAO bathymetry model in the Arctic. This study is focused on an assessment of differences between the GEBCO_08 (a derivative of the IBCAO grid), S&S and the SRTM30_Plus global compilations in the Arctic. Differences between the grids were evaluated in terms of quality metrics, which were defined as important when choosing a bathymetry grid, in particular: depth accuracy, internal consistency and interpolation accuracy. Independent, high-resolution and accuracy multibeam sonar (MBES) derived grids, provided by the Geological Institute Russian Academy of Sciences, were used as a ground truth against which the global compilations were compared. The independent MBES grids occupied six sub-regions with distinct differences in morphology as well as accuracy and distribution of source data used for the construction of the global compilation grids; this allowed addressing regional differences between the grids. In terms of accuracy, GEBCO_08 performs better than S&S and SRTM30_Plus over the three out of six sub-regions mainly due to better source data coverage and proper sound speed corrections applied to the source data. S&S and SRTM30_Plus grids perform similar to or slightly better than GEBCO_08 in deep areas. Poor performance of S&S and SRTM30_Plus was observed within shelf areas with the standard deviation of ...