Submarine melting of glaciers in Greenland amplified by atmospheric warming
Submarine melting of glaciers in Greenland amplified by atmospheric warming
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DOI：
10.1038/s41561-022-01035-9
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发表时间：
2022-10
影响因子：
18.3
通讯作者：
D. Slater;F. Straneo
中科院分区：
文献类型：
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作者：
D. Slater;F. Straneo
自1992年以来，格陵兰冰盖的冰量迅速减少，部分原因是地表融化加剧和冰流加速。后者通常被归因于海洋变暖，海洋变暖加剧了格陵兰岛海洋冰川前沿的海底融化。然而，通过将冰盖表面的融水释放到海洋中，这激发了冰川附近的海洋环流，反过来又将热量从海洋传递到冰中，即使在海洋没有变暖的情况下，变暖的大气也会加速海底的融化。然而，大气和海洋变暖在推动海底融化加速方面的相对重要性尚未得到量化。在这里，我们重建了1979年至2018年格陵兰岛海洋冰川的海底融化速度，并估计了由此产生的动态质量损失。我们表明，在南格陵兰岛，海底融化的变化确实是由海洋控制的，但相反，大气在西北地区占主导地位。在冰盖尺度上，大气在控制海底融化和随后的动态质量损失方面起着一级作用。我们的研究结果挑战了将动态质量损失单独归因于海洋变暖的观点，并表明大气变暖放大了海洋对格陵兰冰盖的影响。
Rapid ice loss from the Greenland ice sheet since 1992 is due in equal parts to increased surface melting and accelerated ice flow. The latter is conventionally attributed to ocean warming, which has enhanced submarine melting of the fronts of Greenland’s marine-terminating glaciers. Yet, through the release of ice sheet surface meltwater into the ocean, which excites near-glacier ocean circulation and in turn the transfer of heat from ocean to ice, a warming atmosphere can increase submarine melting even in the absence of ocean warming. The relative importance of atmospheric and oceanic warming in driving increased submarine melting has, however, not been quantified. Here, we reconstruct the rate of submarine melting at Greenland’s marine-terminating glaciers from 1979 to 2018 and estimate the resulting dynamic mass loss. We show that in south Greenland, variability in submarine melting was indeed governed by the ocean, but, in contrast, the atmosphere dominated in the northwest. At the ice sheet scale, the atmosphere plays a first-order role in controlling submarine melting and the subsequent dynamic mass loss. Our results challenge the attribution of dynamic mass loss to ocean warming alone and show that a warming atmosphere has amplified the impact of the ocean on the Greenland ice sheet.