Aerial Photographs Reveal Late–20th-Century Dynamic Ice Loss in Northwestern Greenland
Aerial Photographs Reveal Late–20th-Century Dynamic Ice Loss in Northwestern Greenland
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航空照片揭示了格陵兰岛西北部 20 世纪末的动态冰损失
DOI：
10.1126/science.1220614
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发表时间：
2012
期刊：
影响因子：
56.9
通讯作者：
E. Willerslev
中科院分区：
文献类型：
--
作者：
K. Kjær;S. Khan;N. Korsgaard;J. Wahr;J. Bamber;R. Hurkmans;M. R. van den Broeke;Lars H. Timm;K. Kjeldsen;A. Bjørk;N. K. Larsen;L. Jørgensen;Anders Færch;E. Willerslev
正在消失的冰的图片 全球变暖正在通过融化、升华和侵蚀其边缘来加速冰盖质量的损失。为了提供更好的背景来理解当代的损失，需要对最近的历史进行更长的记录。克亚尔等人。 （第 569 页）通过将存档的航空照片与数字高程模型结合使用，并将其结果与更新的数据进行比较，将格陵兰冰盖西北边缘的减薄记录追溯到 1980 年代中期。格陵兰岛西北部在过去三十年中经历了两次动态冰损事件。局部冰损失似乎是由可预测的表面过程（在十年时间尺度上运行）和涉及冰在 3 至 5 年期间快速移动的过程相结合造成的，这些过程表现出强烈的区域差异。追溯到 20 世纪 80 年代中期的存档照片有助于展示动态变薄在格陵兰岛冰块损失中的作用。预计全球变暖将对格陵兰冰盖及其对全球海平面上升的贡献产生深远影响。最近格陵兰岛西北部的质量损失非常严重。利用航空照片，我们制作了数字高程模型，并将最近观察到的边缘动态变薄的时间记录延长至 20 世纪 80 年代中期。我们揭示了格陵兰冰盖西北部边缘的两次独立的动态冰损失事件：1985年至1993年和2005年至2010年，这两次事件被有限的质量变化分开。我们的结果表明，该区域的冰质量变化主要是由短暂的动态冰损失事件引起的，而不是表面质量平衡的变化引起的。这一发现对格陵兰冰盖未来对全球气温升高的反应的预测提出了挑战。
A Picture of Disappearing Ice Global warming is accelerating the loss of ice sheet mass by melting, sublimation, and erosion of their margins. In order to provide a better context for understanding contemporary losses, a longer record of the recent past is needed. Kjær et al. (p. 569) extend the record of thinning along the northwest margin of the Greenland Ice Sheet back to the mid-1980s, by using archived aerial photographs in conjunction with a digital elevation model and comparing their results to more recent data. Northwestern Greenland has experienced two dynamic ice loss events in the past three decades. Local ice loss appears to be caused by a combination of predictable surface processes that operate over decadal time scales and ones that involve the rapid movement of ice over periods of 3 to 5 years that exhibit strong regional differences. Archived photographs extending back to the mid-1980s help show the role of dynamic thinning in ice mass loss from Greenland. Global warming is predicted to have a profound impact on the Greenland Ice Sheet and its contribution to global sea-level rise. Recent mass loss in the northwest of Greenland has been substantial. Using aerial photographs, we produced digital elevation models and extended the time record of recent observed marginal dynamic thinning back to the mid-1980s. We reveal two independent dynamic ice loss events on the northwestern Greenland Ice Sheet margin: from 1985 to 1993 and 2005 to 2010, which were separated by limited mass changes. Our results suggest that the ice mass changes in this sector were primarily caused by short-lived dynamic ice loss events rather than changes in the surface mass balance. This finding challenges predictions about the future response of the Greenland Ice Sheet to increasing global temperatures.