Abstract
AbstractThe recently published Bedmap2 datasets mark the culmination of several decades of subice and subocean Antarctic topographic surveying by many nations, but maps of the topographic data distribution show that in the global context, the Antarctic bed remains very poorly sampled. Most of the remaining large unmapped areas on Earth lie under Antarctic ice and polar surveying continues to be difficult and expensive, thus it is important to identify where future efforts should be concentrated. A survey of 75 experts in various aspects of polar science shows that a lack of adequate topographic data is an important constraint in several themes, but the data gaps and the data needs do not tend to coincide. There is strong demand for higher resolution surveying in previously visited areas, particularly in the most dynamic and most rapidly changing regions as identified by glaciologists, oceanographers, hydrologists, biologists and geomorphologists, while geologists and ice core scientists focus on the most important areas for understanding Antarctica over deeper time. The data requirements identified here could be addressed for most areas given sufficient time and funding, but the technology needed to survey the interiors of the large ice shelf cavities has only just been developed.
Highlights
Topographic maps of the landscape hidden below the polar seas and the ice cover of Greenland and Antarctica (Fig. 1) are fundamental to our understanding of the tectonic and geomorphological processes that shape the Earth in these regions
For Antarctica, Bedmap2 consists of a digital elevation model of the continent’s surface and the subice and submarine bed south of 60°S, plus a seamless grid of ice thickness for the ice sheets and floating ice shelves. It is constructed from satellite and airborne altimetry and the entire archive of Southern Ocean bathymetry and available Antarctic ice thickness measurements collected since the beginning of the scientific era
The distribution of survey data for the Greenland and Antarctic ice sheets and neighbouring seas shows that Antarctic topography is considerably less well sampled than that in the Arctic, and there remain large areas that are uncharted
Summary
Topographic maps of the landscape hidden below the polar seas and the ice cover of Greenland and Antarctica (Fig. 1) are fundamental to our understanding of the tectonic and geomorphological processes that shape the Earth in these regions. Bedmap provides much improved estimates of ice sheet volume and potential sea level contribution and, perhaps most strikingly, our first view of a recognizable landscape of troughs, valleys and mountain ranges, the last continental landscape on Earth to be mapped For both Antarctica and Greenland, survey data have been won at considerable expense over the last few decades by ground, airborne and shipborne teams from many nations working in difficult conditions with different goals. The gridding and interpolation used to generate a continuous surface from such heterogeneous data introduce artefacts where by failing to capture the fine detail present along survey lines and interpolating over gaps in the data (Fig. 5b & c) These two issues lead to misrepresentation of the bed topography even directly under survey lines and affect the steep-sided, deep glacier troughs with high ice flux that are critical in controlling ice sheet mass balance. The scientific case for new surveys and new topographic grids may not correlate with the filling of obvious blanks in the current map
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