Pathways of Meltwater Export from Petermann Glacier, Greenland
Pathways of Meltwater Export from Petermann Glacier, Greenland
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DOI：
10.1175/jpo-d-16-0161.1
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发表时间：
2017-02-01
影响因子：
3.5
通讯作者：
Munchow, Andreas
中科院分区：
文献类型：
--
作者：
Heuze, Celine;Wahlin, Anna;Munchow, Andreas
大西洋水的入侵导致格陵兰海洋冰川和冰架的底部融化，例如格陵兰西北部的彼得曼冰川。由此产生的冰川融化水的命运在很大程度上是未知的。本文利用2015年8月在彼得曼峡湾和邻近的纳尔海峡破冰船(I/B)奥登进行研究巡航期间收集的水文观测数据对其进行了调查。三端元混合方法提供了彼得曼冰架融化水的浓缩。在邻近纳尔斯海峡的所有铸模中都发现了来自彼得曼的融水，其中格陵兰沿岸开尔文波相位传播方向的融水浓度最高。来自Petermann的融水主要以斜压边界流的形式流出峡湾的东北侧，最大融水浓度的深度约为150m，并沿其路径浅化。在将峡湾与周围海洋隔开的外海床，大约0.3mSv(1 Sv相当于10(6)m(3)S(-1))的基础融水离开峡湾，深度在100m到300m之间。2015年8月，冰川末端附近的总地转热量和淡水通量与2009年8月估计的相似，之前的两次重大崩解事件使彼得曼的冰舌长度减少了近三分之一，尽管大西洋水变暖了。这些结果提供了一个基线，但也强调了适当评估随着大西洋水变暖格陵兰质量损失对海洋环流和海平面的影响所需的因素。
Intrusions of Atlantic Water cause basal melting of Greenland's marine-terminating glaciers and ice shelves, such as that of Petermann Glacier, in northwest Greenland. The fate of the resulting glacial meltwater is largely unknown. It is investigated here, using hydrographic observations collected during a research cruise in Petermann Fjord and adjacent Nares Strait onboard icebreaker (I/B) Oden in August 2015. A three end-member mixing method provides the concentration of Petermann ice shelf meltwater. Meltwater from Petermann is found in all of the casts in adjacent Nares Strait, with the highest concentration along the Greenland coast in the direction of Kelvin wave phase propagation. The meltwater from Petermann mostly flows out on the northeast side of the fjord as a baroclinic boundary current, with the depth of maximum meltwater concentrations approximately 150m and shoaling along its pathway. At the outer sill, which separates the fjord from the ambient ocean, approximately 0.3 mSv (1 Sv equivalent to 10(6) m(3) s(-1)) of basal meltwater leaves the fjord at depths between 100 and 300 m. The total geostrophic heat and freshwater fluxes close to the glacier's terminus in August 2015 were similar to those estimated in August 2009, before the two major calving events that reduced the length of Petermann's ice tongue by nearly a third and despite warmer inflowing Atlantic Water. These results provide a baseline but also highlight what is needed to assess properly the impact on ocean circulation and sea level of Greenland's mass loss as the Atlantic Water warms up.