Bathymetry constrains ocean heat supply to Greenland's largest glacier tongue
Bathymetry constrains ocean heat supply to Greenland's largest glacier tongue
复制标题
测深限制了格陵兰岛最大冰川舌的海洋热量供应
DOI：
10.1038/s41561-019-0529-x
复制
发表时间：
2020
影响因子：
18.3
通讯作者：
Schaffer J
中科院分区：
文献类型：
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作者：
Schaffer J
格陵兰冰盖的质量损失在过去二十年中有所增加，目前占全球海平面上升的25%。这是由于大气变暖导致地表融化增加，以及海洋热输送迫使海洋冰川退缩和加速。我们使用了2016年至2017年在格陵兰东北部79北冰川浮舌前收集的船舶剖面、水深数据和系泊时间序列，包括温度、盐度和水流速度。这些观测表明，温暖的大西洋水全年通过狭窄的通道流入海底，受到屏障的限制。相关的热输送导致浮动冰舌底部的平均融化速率为10.4±3.1 m /年。大西洋暖水和较冷的海水之间的界面高度控制着海洋热输送的时间变率。历史水文数据表明，界面高度在过去二十年中有所上升，这意味着基础融化速率的增加。邻近的Zachariæ Isstrøm的额外温度剖面表明，这里的海洋热输送同样受到近冰川的控制。我们的结论是，冰川附近的海洋热输送对冰川的稳定性起着至关重要的作用。
Mass loss from the Greenland ice sheet has increased over the past two decades, currently accounting for 25% of global sea-level rise. This is due to increased surface melt driven by atmospheric warming and the retreat and acceleration of marine-terminating glaciers forced by oceanic heat transport. We use ship-based profiles, bathymetric data and moored time series from 2016 to 2017 of temperature, salinity and water velocity collected in front of the floating tongue of the 79 North Glacier in Northeast Greenland. These observations indicate that a year-round bottom-intensified inflow of warm Atlantic Water through a narrow channel is constrained by a sill. The associated heat transport leads to a mean melt rate of 10.4 ± 3.1 m yr–1on the bottom of the floating glacier tongue. The interface height between warm Atlantic Water and colder overlying water above the sill controls the ocean heat transport’s temporal variability. Historical hydrographic data show that the interface height has risen over the past two decades, implying an increase in the basal melt rate. Additional temperature profiles at the neighbouring Zachariæ Isstrøm suggest that ocean heat transport here is similarly controlled by a near-glacier sill. We conclude that near-glacier, sill-controlled ocean heat transport plays a crucial role for glacier stability.