Ice flow dynamics and surface meltwater flux at a land-terminating sector of the Greenland ice sheet
Ice flow dynamics and surface meltwater flux at a land-terminating sector of the Greenland ice sheet
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DOI：
10.3189/2013jog12j143
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发表时间：
2013-01-01
影响因子：
3.4
通讯作者：
Jones, Glenn A.
中科院分区：
文献类型：
--
作者：
Fitzpatrick, Andrew A. W.;Hubbard, Alun;Jones, Glenn A.
我们提出了两个对比鲜明的融化季节的2009-10年在罗素冰川流域，格陵兰冰盖的西部，陆地终端部门，其中包括K（angerlussuaq）-样带的卫星推导的速度模式。结果突出了巨大的空间异质性流量，表明结构控制，如基岩几何形状管理到个人出口槽冰流量。结果还揭示了强大的季节性流动变化延伸57公里冰川海拔1200米，最大的加速度（100%，超过11天）发生在10公里的边缘与春季融化。到2010年7月下旬，在融化和径流高峰前两周，2400 km（2）的集水区中有48%已经减缓到低于冬季平均值。这一观察结果支持了这样的假设：冰下水文系统从低效的分布式系统演变为高效的排水系统，调节水流动态。尽管如此，与2009年平均融化年的扰动相比，2010年创纪录融化年的累积表面通量仍然更大。这项研究支持的命题，当地的表面融水径流耦合到基础水文驱动冰盖动态，虽然效果是非线性的，我们的观察表明，更大的融水径流产生增加净通量在这一部门的冰盖。
We present satellite-derived velocity patterns for the two contrasting melt seasons of 2009-10 across Russell Glacier catchment, a western, land-terminating sector of the Greenland ice sheet which encompasses the K(angerlussuaq)-transect. Results highlight great spatial heterogeneity in flow, indicating that structural controls such as bedrock geometry govern ice discharge into individual outlet troughs. Results also reveal strong seasonal flow variability extending 57 km up-glacier to 1200 m elevation, with the largest acceleration (100% over 11 days) occurring within 10 km of the margin coincident with spring melt. By late July 2010, 2 weeks before peak melt and runoff, 48% of the 2400 km(2) catchment had slowed to less than the winter mean. This observation supports the hypothesis that the subglacial hydrological system evolves from an inefficient distributed to an efficient drainage system, regulating flow dynamics. Despite this, the cumulative surface flux over the record melt year of 2010 was still greater compared with the perturbation over the average melt year of 2009. This study supports the proposition that local surface meltwater runoff couples to basal hydrology driving ice-sheet dynamics, and although the effect is nonlinear, our observations indicate that greater meltwater runoff yields increased net flux over this sector of the ice sheet.