Improvement to the International Bathymetric Chart of the Arctic Ocean (IBCAO): Updating the Data Base and the Grid Model

The project to develop the IBCAO grid model was initiated in 1997 with the objective of providing to the Arctic research community an improved portrayal of the seabed north of 64-deg N, in a form suitable for digital manipulation and visualization. The model was constructed from a compilation of all single-beam and multibeam echo soundings that were available for the polar region, complemented where appropriate by newly released contour information. The grid features a cell size of 2.5 x 2.5 km on a polar stereographic projection; it is constructed on the WGS 84 datum, with true scale at 75-deg N. Designated the Beta Version, a preliminary implementation of IBCAO was introduced to the geophysical community in December 1999, and released four months later as a digital grid that could be downloaded from a project website hosted by the National Geophysical Data Center in Boulder, CO. Since that release, the Beta Version has seen widespread use in Earth Science applications, with the website continuing to garner between 500 and 1000 visitors per week; this reportedly makes it one of the most heavily-visited of all NGDC websites. IBCAO has since been updated with the development of Version 1.0, which incorporates new information and formats, along with an expanded range of bathymetric products that will be released for public use through the same project website. Improvements include corrections to errors that were identified off Svalbard, in Canada Basin, and in Barrow Strait, as well as contributions of significant new data sets that were collected by the Norwegian Petroleum Directorate and the Alfred Wegener Institute off Norway and Svalbard, in Fram Strait, and over the Lomonosov Ridge. In addition, the portrayal of the Alaskan landmass was enhanced with a new topographic model extracted from NGDC's GLOBE data set. New formats include downloadable Cartesian grids that can be imported directly into ArcInfo and Intergraph's module Terrain Analyst. A geographic grid has been produced as well, with a resolution of 1' x 1' for compatibility with the global grid of bathymetry that is now under construction by a working group operating under the auspices of the General Bathymetric Chart of the Oceans (GEBCO). New products include a suite of bathymetric contours derived from the grid at depths ranging from 20 metres to 5000 metres, and poster-sized Postscript maps showing isobaths printed over a shaded relief background. These latest developments reflect a commitment to maintain IBCAO as a `live' product for the foreseeable future, with periodic upgrades to improve its quality and usefulness. >http://www.ngdc.noaa.gov/mgg/bathymetry/arctic/arctic.html</a>