Repeat optical satellite images reveal widespread and long term decrease in land-terminating glacier speeds
Repeat optical satellite images reveal widespread and long term decrease in land-terminating glacier speeds
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DOI：
10.5194/tc-6-467-2012
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发表时间：
2012-04
期刊：
影响因子：
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通讯作者：
T. Heid;A. Kääb
中科院分区：
文献类型：
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作者：
T. Heid;A. Kääb
通过对重复的光学卫星图像进行匹配，现在可以研究世界大区域内的冰川动态，也可以研究区域间的冰川动态，以增进对冰川动态在空间和时间上的了解。在这项研究中，我们调查了世界大部分地区出现的负冰川质量平衡是否导致冰川改变了它们的速度。研究的地区是帕米尔、高加索、佩尼冰帽、阿拉斯加山脉和巴塔哥尼亚。此外，我们还推导出喀喇昆仑地区的速度变化，该地区被认为具有正质量平衡，并包含许多涌浪型冰川。我们发现，在过去的几十年里，绘制的五个负物质平衡地区的冰川以平均每十年的速度下降了：帕米尔冰川43%，高加索冰川8%，彭尼冰帽冰盖25%，阿拉斯加冰盖11%，巴塔哥尼亚冰盖20%。喀喇昆仑的冰川总体上加快了速度，但这一地区最突出的是汹涌的冰川和流动不稳定的冰川。因此，计算出的平均速度变化对该地区并不具有代表性。
By matching of repeat optical satellite images it is now possible to investigate glacier dynamics within large regions of the world and also between regions to improve knowledge about glacier dynamics in space and time. In this study we investigate whether the negative glacier mass balance seen over large parts of the world has caused the glaciers to change their speeds. The studied regions are Pamir, Caucasus, Penny Ice Cap, Alaska Range and Patagonia. In addition we derive speed changes for Karakoram, a region assumed to have positive mass balance and that contains many surge-type glaciers. We find that the mapped glaciers in the five regions with negative mass balance have over the last decades decreased their velocity at an average rate per decade of: 43 % in the Pamir, 8 % in the Caucasus, 25 % on Penny Ice Cap, 11 % in the Alaska Range and 20 % in Patagonia. Glaciers in Karakoram have generally increased their speeds, but surging glaciers and glaciers with flow instabilities are most prominent in this area. Therefore the calculated average speed change is not representative for this area.