Rezvanbehbahani Soroush, Stearns Leigh A, Keramati Ramtin, Shankar Siddharth, van der Veen C J
Department of Geology, University of Kansas, Lawrence, KS USA.
Center for Remote Sensing of Ice Sheets, University of Kansas, Lawrence, KS USA.
Commun Earth Environ. 2020;1(1):31. doi: 10.1038/s43247-020-00032-3. Epub 2020 Oct 15.
Icebergs represent nearly half of the mass loss from the Greenland Ice Sheet and provide a distributed source of freshwater along fjords which can alter fjord circulation, nutrient levels, and ultimately the Meridional Overturning Circulation. Here we present analyses of high resolution optical satellite imagery using convolutional neural networks to accurately delineate iceberg edges in two East Greenland fjords. We find that a significant portion of icebergs in fjords are comprised of small icebergs that were not detected in previously-available coarser resolution satellite images. We show that the preponderance of small icebergs results in high freshwater delivery, as well as a short life span of icebergs in fjords. We conclude that an inability to identify small icebergs leads to inaccurate frequency-size distribution of icebergs in Greenland fjords, an underestimation of iceberg area (specifically for small icebergs), and an overestimation of iceberg life span.
冰山约占格陵兰冰盖质量损失的一半，并沿着峡湾提供分散的淡水源，这会改变峡湾环流、营养水平，最终影响经向翻转环流。在此，我们展示了利用卷积神经网络对高分辨率光学卫星图像进行的分析，以准确描绘东格陵兰两个峡湾中的冰山边缘。我们发现，峡湾中很大一部分冰山是由先前分辨率较粗的卫星图像中未检测到的小冰山组成。我们表明，小冰山占主导导致了高淡水输送量，以及峡湾中冰山的短寿命。我们得出结论，无法识别小冰山会导致格陵兰峡湾中冰山频率 - 尺寸分布不准确、冰山面积估计不足（特别是对于小冰山）以及冰山寿命估计过高。
