Partitioning effects from ocean and atmosphere on the calving stability of Kangerdlugssuaq Glacier, East Greenland
Partitioning effects from ocean and atmosphere on the calving stability of Kangerdlugssuaq Glacier, East Greenland
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DOI：
10.3189/2012aog60a087
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发表时间：
2012-01-01
影响因子：
2.9
通讯作者：
van den Broeke, Michiel
中科院分区：
文献类型：
--
作者：
Christoffersen, Poul;O'Leary, Martin;van den Broeke, Michiel
我们使用7公里的撤退Kangerdlugssuaq冰川（KG），东格陵兰岛，研究大气强迫和冰/海洋相互作用的机制，相互作用和相对意义。1991年、1993年和2004年的水文数据表明，Kangerdlugssuaq峡湾（KF）的亚热带沃茨很常见，2004年的表面沃茨相对于1991年和1993年温暖。尽管如此，1991年的主要水柱仍然是最温暖的。我们认为，虽然流入峡湾的亚热带沃茨提供了一个快速冰川退缩的环境，退缩的触发取决于其他环境因素。在我们对KG和KF的研究中，突出的气候变量是气温和下降风。在2004/05年冬季，当KG回落时，两者都有很强的正异常。我们表明，冰前混杂岩是不存在的，峡湾冻结没有发生，直到2005年4月11日，由于温暖和多风的条件。我们证明，这种设置是不寻常的，并假设暴露在冬季开放水域造成的撤退。冰前融化率的计算表明，排放的基础融水，首先从径流，随后从摩擦基底加热，应加强冰川和峡湾之间的相互作用。
We use the 7 km retreat of Kangerdlugssuaq Glacier (KG), East Greenland, to examine the mechanisms, interactions and relative significance of atmospheric forcing and ice/ocean interactions. Hydrographic data from 1991, 1993 and 2004 show that subtropical waters are common in Kangerdlugssuaq Fjord (KF), and that surface waters were warm in 2004 relative to 1991 and 1993. The main water column was nonetheless warmest in 1991. We contend that while flow of subtropical waters into fjords provides a setting in which rapid glacier retreat can occur, the triggering of retreat depends on additional environmental factors. The climatic variables standing out in our study of KG and KF are air temperature and katabatic winds. Both had strong positive anomalies during winter 2004/05, when KG retreated. We show that proglacial ice melange was absent and that fjord freeze-up did not occur until 11 April 2005, due to warm and windy conditions. We demonstrate that this setting is unusual and hypothesize that exposure to open water in winter months caused the retreat. Calculation of ice-front melt rates shows that discharge of basal meltwater, first from runoff and subsequently from frictional basal heating, should intensify the interaction between glacier and fjord.