Exceptional Retreat of Kangerlussuaq Glacier, East Greenland, Between 2016 and 2018
Exceptional Retreat of Kangerlussuaq Glacier, East Greenland, Between 2016 and 2018
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DOI：
10.3389/feart.2019.00123
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发表时间：
2019-05-31
影响因子：
2.9
通讯作者：
Lea, James M.
中科院分区：
文献类型：
--
作者：
Brough, Stephen;Carr, J. Rachel;Lea, James M.
Kangerlussuaq冰川是格陵兰岛最大的冰川出口之一，约占格陵兰冰盖所有冰流量的5%。2018年，康克鲁斯瓦克冰锋达到了自1932年开始观测以来最大的退缩位置。我们确定退缩和之间的关系：（一）冰速度;和（二）表面海拔变化，以评估退缩对冰川主干的影响。在2016年至2018年期间，冰川退缩了大约5公里，并使Kangerlussuaq冰锋过度加深（大约15公里长）。与此同时，冰川由于冰流接近终点的加速而变薄。冰下地形意味着2016-2018年的终端衰退可能会引发退缩，变薄和冰川加速之间的一系列反馈，导致流量和海平面上升贡献的快速和高幅度增加。动态变薄可能会持续到冰川到达向上倾斜的河床，类似于其目前位置的内陆10公里。将这些非线性过程纳入到2100年及以后的冰盖预测模型中，对于准确预测冰盖对海平面上升的影响至关重要。
Kangerlussuaq Glacier is one of Greenland's largest tidewater outlet glaciers, accounting for approximately 5% of all ice discharge from the Greenland ice sheet. In 2018 the Kangerlussuaq ice front reached its most retreated position since observations began in 1932. We determine the relationship between retreat and: (i) ice velocity; and (ii) surface elevation change, to assess the impact of the retreat on the glacier trunk. Between 2016 and 2018 the glacier retreated similar to 5 km and brought the Kangerlussuaq ice front into a major (similar to 15 km long) overdeepening. Coincident with this retreat, the glacier thinned as a result of near-terminus acceleration in ice flow. The subglacial topography means that 2016-2018 terminus recession is likely to trigger a series of feedbacks between retreat, thinning, and glacier acceleration, leading to a rapid and high-magnitude increase in discharge and sea level rise contribution. Dynamic thinning may continue until the glacier reaches the upward sloping bed similar to 10 km inland of its current position. Incorporating these non-linear processes into prognostic models of the ice sheet to 2100 and beyond will be critical for accurate forecasting of the ice sheet's contribution to sea level rise.