Outlet glacier response to forcing over hourly to interannual timescales, Jakobshavn Isbræ, Greenland
Outlet glacier response to forcing over hourly to interannual timescales, Jakobshavn Isbræ, Greenland
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格陵兰岛雅各布港伊斯布拉的出口冰川对每小时至年际时间尺度强迫的响应
DOI：
10.3189/2012jog12j065
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发表时间：
2012
影响因子：
3.4
通讯作者：
I. Joughin
中科院分区：
文献类型：
--
作者：
D. Podrasky;M. Truffer;M. Fahnestock;J. Amundson;R. Cassotto;I. Joughin
21世纪初，格陵兰岛Jakobshavn isbryshrn浮冰舌的消失与变薄、退缩和加速的模式同时发生，导致对全球海平面的贡献增强。这些在年代际尺度上的变化已经有了很好的记录。在这里，我们确定了冰川如何响应较短时间尺度上的强迫，例如地表融化的变化、冰川上湖泊的排水和末端位置的季节性波动。从2006年到2008年，断断续续地监测了冰的运动和地表融化。在冰川中心线上游20-50公里处部署了双频GPS。利用同一时期记录的地表空气温度驱动的烧蚀温度指数模型填补了表面熔体测量的空白。我们的研究结果证实了控制Jakobshavn isbrszv上速度的主要因素是终端位置和几何形状的前提。我们还观察到，地表速度与融水输入表现出复杂的关系：在日时间尺度上，地表速度与融水输入的变化密切相关；然而，在季节时间尺度上，观察到更长、更强烈的融化季节有效地减少了全年冰川的总冰流量
Abstract The loss of the floating ice tongue on Jakobshavn Isbrӕ, Greenland, in the early 2000s has been concurrent with a pattern of thinning, retreat and acceleration leading to enhanced contribution to global sea level. These changes on decadal timescales have been well documented. Here we identify how the glacier responds to forcings on shorter timescales, such as from variations in surface melt, the drainage of supraglacial lakes and seasonal fluctuations in terminus position. Ice motion and surface melt were monitored intermittently from 2006 to 2008. Dual-frequency GPS were deployed 20–50 km upstream of the terminus along the glacier center line. Gaps in surface melt measurements were filled using a temperature-index model of ablation driven by surface air temperatures recorded during the same time period. Our results corroborate the premise that the primary factors controlling speeds on Jakobshavn Isbrӕ are terminus position and geometry. We also observe that surface speeds demonstrate a complex relationship with meltwater input: on diurnal timescales, velocities closely match changes in water input; however, on seasonal timescales a longer, more intense melt season was observed to effectively reduce the overall ice flow of the glacier for the whole year
影响因子：
18.3
作者：
Bartholomew, Ian;Nienow, Peter;Sole, Andrew
通讯作者：
Sole, Andrew