Non-surface mass balance is non-negligible for glaciers in Iceland. Several Icelandic glaciers are in the neo-volcanic zone where a combination of geothermal activity, volcanic eruptions and geothermal heat flux much higher than the global average lead to basal melting close to 150 mm w.e. a−1 for the Mýrdalsjökull ice cap and 75 mm w.e. a−1 for the largest ice cap, Vatnajökull. Energy dissipation in the flow of water and ice is also rather large for the high-precipitation, temperate glaciers of Iceland resulting in internal and basal melting of 20–150 mm w.e. a−1. The total non-surface melting of glaciers in Iceland in 1995–2019 was 45–375 mm w.e. a−1 on average for the main ice caps, and was largest for Mýrdalsjökull, the south side of Vatnajökull and Eyjafjallajökull. Geothermal melting, volcanic eruptions and the energy dissipation in the flow of water and ice, as well as calving, all contribute, and thus these components should be considered in mass-balance studies. For comparison, the average mass balance of glaciers in Iceland since 1995 is −500 to −1500 mm w.e. a−1. The non-surface mass balance corresponds to a total runoff contribution of 2.1 km3 a−1 of water from Iceland.

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冰岛冰川的非地表质量平衡

冰岛冰川的非地表质量平衡是不可忽略的。几个冰岛冰川位于新火山带，地热活动、火山爆发和地热热通量远高于全球平均水平，导致基底融化接近 150 毫米-1对于 Mýrdalsjökull 冰盖和 75 毫米，我们-1最大的冰盖瓦特纳冰川。对于冰岛的高降水量温带冰川，水和冰流动中的能量耗散也相当大，导致内部和基底融化 20-150 毫米，我们 a-1. 1995-2019 年冰岛冰川的非表面总融化量为 45-375 毫米，我们 a-1平均而言，主要冰盖的面积最大，米达尔斯冰川、瓦特纳冰川南侧和艾雅法拉冰川最大。地热融化、火山喷发、水和冰流动中的能量耗散以及产犊，都有贡献，因此在质量平衡研究中应考虑这些成分。相比之下，自 1995 年以来冰岛冰川的平均质量平衡为 -500 至 -1500 毫米-1. 非地表质量平衡对应于 2.1 公里的总径流贡献3一种-1来自冰岛的水。