A new bed elevation dataset for Greenland
A new bed elevation dataset for Greenland
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DOI：
10.5194/tc-7-499-2013
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发表时间：
2013-01-01
期刊：
影响因子：
5.2
通讯作者：
Steinhage, D.
中科院分区：
文献类型：
--
作者：
Bamber, J. L.;Griggs, J. A.;Steinhage, D.
我们展示了一个新的格陵兰岛床面高程数据集，它是由20世纪70年代到2012年间进行的多次机载冰厚测量数据组合而成。大约使用了420000线公里的机载数据，其中约70%是2000年以后收集的，2000年进行了上一次全面的汇编。机载数据与非冰川地形的卫星高程数据相结合，生成了整个岛屿（包括冰川 - 无冰边界）一致的床面数字高程模型（DEM）。借助主要来自北极汇编的测深数据，该DEM延伸到了大陆边缘。对于存在冰架的地方，通过结合表面高程和雷达探测确定冰厚。飞行航线之间的跨轨间距使得在冰盖的重要区域需要以1公里的间距进行插值。还生成了冰面高程网格、DEM的误差估计、冰厚以及数据采样密度，同时还有陆地/海洋/接地冰/浮冰的掩模。床面高程误差范围从最小的±10米到约±300米，这是与观测点的距离以及当地地形变化的函数。与2001年发布的汇编进行比较，突出了新数据集在分辨率方面的提高，特别是在冰盖边缘，那里的冰流速最高，冰动力学变化也最为显著。我们估计，我们的陆地冰掩模所包含的冰量将使平均海平面上升7.36米，这还不包括冰盖消融过程中可能发生的任何固体地球效应。
We present a new bed elevation dataset for Greenland derived from a combination of multiple airborne ice thickness surveys undertaken between the 1970s and 2012. Around 420 000 line kilometres of airborne data were used, with roughly 70% of this having been collected since the year 2000, when the last comprehensive compilation was undertaken. The airborne data were combined with satellite-derived elevations for non-glaciated terrain to produce a consistent bed digital elevation model (DEM) over the entire island including across the glaciated-ice free boundary. The DEM was extended to the continental margin with the aid of bathymetric data, primarily from a compilation for the Arctic. Ice thickness was determined where an ice shelf exists from a combination of surface elevation and radar soundings. The across-track spacing between flight lines warranted interpolation at 1 km postings for significant sectors of the ice sheet. Grids of ice surface elevation, error estimates for the DEM, ice thickness and data sampling density were also produced alongside a mask of land/ocean/grounded ice/floating ice. Errors in bed elevation range from a minimum of +/- 10m to about +/- 300 m, as a function of distance from an observation and local topographic variability. A comparison with the compilation published in 2001 highlights the improvement in resolution afforded by the new datasets, particularly along the ice sheet margin, where ice velocity is highest and changes in ice dynamics most marked. We estimate that the volume of ice included in our land-ice mask would raise mean sea level by 7.36 m, excluding any solid earth effects that would take place during ice sheet decay.