Variability in ice motion at a land-terminating Greenlandic outlet glacier: the role of channelized and distributed drainage systems
Variability in ice motion at a land-terminating Greenlandic outlet glacier: the role of channelized and distributed drainage systems
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DOI：
10.1017/jog.2016.36
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发表时间：
2016-06
影响因子：
3.4
通讯作者：
T. Cowton;P. Nienow;A. Sole;I. Bartholomew;D. Mair
中科院分区：
文献类型：
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作者：
T. Cowton;P. Nienow;A. Sole;I. Bartholomew;D. Mair
我们结合实地观测和水文模拟来研究融水输入的变化影响格陵兰岛陆地出口冰川冰运动的机制。我们发现水平冰速度、垂直冰速度和模拟的冰下压力在融化季节过程中有着密切的一致性。在此基础上，我们认为水平和垂直冰速的变化主要反映了空腔扩张和收缩期间基底冰的位移，这一过程本身是由源自冰下通道的基底水压力波动驱动的。这一过程没有被连接水压和基本流速的传统滑动定律所捕获，这可能会妨碍在冰川水文和动力学耦合模型中模拟实际的冰速日变化到季节变化。
We use a combination of field observations and hydrological modelling to examine the mechanisms through which variability in meltwater input affects ice motion at a land-terminating Greenlandic outlet glacier. We find a close agreement between horizontal ice velocity, vertical ice velocity and modelled subglacial water pressure over the course of a melt season. On this basis, we argue that variation in horizontal and vertical ice velocity primarily reflects the displacement of basal ice during periods of cavity expansion and contraction, a process itself driven by fluctuations in basal water pressure originating in subglacial channels. This process is not captured by traditional sliding laws linking water pressure and basal velocity, which may hinder the simulation of realistic diurnal to seasonal variability in ice velocity in coupled models of glacial hydrology and dynamics.