Almost half of the Greenland ice sheet's mass loss occurs through iceberg calving at marine terminating glaciers. The presence of buoyant subglacial discharge plumes at these marine termini are thought to increase mass loss both through submarine melting and by undercutting that consequently increases calving rates. Plume models are used to predict submarine melting and undercutting. However, there are few observations that allow these relationships to be tested. Here, we use airborne lidar from the terminus of Helheim Glacier, SE Greenland to measure the bulge induced at the surface by the upwelling plume. We use these measurements to estimate plume discharge rates using a high‐resolution, three‐dimensional plume model. Multiyear observations of the plume are compared to a record of calving from camera and icequake data. We find no evidence to suggest that the presence of a plume, determined by its visibility at the surface, increases the frequency of major calving events and also show that mass loss at the terminus driven directly by plume discharge is significantly less than mass loss from major calving events. The results suggest that the contribution of direct plume‐driven mass loss at deep marine‐terminating glaciers may be less than at shallower termini.

中文翻译：

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冰川下排放羽流对格陵兰东南部海尔海姆冰川产犊，海底融化和梅朗日质量损失的影响

格陵兰岛冰盖几乎一半的质量损失是通过在海洋终端冰川处的冰山崩裂而发生的。人们认为，在这些海洋终点处存在浮冰下的浮冰羽流会通过海底融化和挖底增加产犊率，从而增加质量损失。羽状模型用于预测海底融化和咬蚀。但是，很少有观察结果可以测试这些关系。在这里，我们使用东南部格陵兰岛Helheim Glacier终点的机载激光雷达来测量上升的羽流在地面上引起的凸起。我们使用这些测量值，通过高分辨率的三维羽状模型来估计羽状排放率。将对烟羽的多年观察结果与从照相机和冰震数据记录的产犊记录进行了比较。我们没有证据表明，由羽状物在表面的可见性决定的羽状物的存在会增加主要产犊事件的发生频率，并且还表明，由羽状物排放直接驱动的末端的质量损失显着小于主要羽化事件的质量损失。产犊事件。结果表明，直接羽流驱动的质量损失在深海海洋终止冰川中的贡献可能小于在浅海末端。