Tidal pacing, skipped slips and the slowdown of Whillans Ice Stream, Antarctica
Tidal pacing, skipped slips and the slowdown of Whillans Ice Stream, Antarctica
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南极洲威兰斯冰流的潮汐节奏、跳跃滑动和减速
DOI：
10.3189/2014jog14j038
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发表时间：
2014
影响因子：
3.4
通讯作者：
M. Pratt
中科院分区：
文献类型：
--
作者：
J. P. Winberry;S. Anandakrishnan;R. Alley;D. Wiens;M. Pratt
本文总结了南极惠兰冰流减速和粘滑运动的新观测结果。我们完善的位置大粘点，抵制滑动事件之间的运动，其位置是由冰下水流的模式控制。我们对冰流的长期速度时间序列的研究表明，十年尺度的减速并不是以稳定的速率发生的，而是在亚十年时间尺度上变化的。这种不稳定的减速调制的时间演变的广泛（约50公里）的表面高程隆起形成在交界处之间的相对狭窄的上游部分的冰流和广泛的冰平原，构成了下游端的WIS。2003年4月和2010年11月的观测结果比较显示，潮汐调制粘滑周期，调节运动的冰原上的显着变化。我们观察到，滑动事件的时间已变得不太经常响应于冰流的上游部分的流速降低。滑动事件的规律性降低减少了滑动事件期间存储的弹性应变的释放，增加了减速速率。
We summarize new observations of the deceleration and stick–slip motion of Whillans Ice Stream (WIS), Antarctica. We refine the location of the large sticky spots that resist motion between slip events, the locations of which are controlled by the patterns of subglacial water flow. Our examination of the long-term velocity time series for the ice stream reveals that the decadal-scale deceleration is not occurring at a steady rate, but varies at the sub-decadal timescale. This unsteady deceleration modulates the temporal evolution of a broad (~50 km across) surface-elevation bulge forming at the junction between the relatively narrow upstream portion of the ice stream and broad ice plain that constitutes the downstream end of WIS. Comparison of observations from April 2003 and November 2010 reveals significant changes in the tidally modulated stick–slip cycle that regulates motion on the ice plain. We observe that the timing of slip events has become less regular in response to decreased flow speed in the upstream portions of the ice stream. The decreased regularity of slip events has reduced the release of stored elastic strain during slip events, increasing the rate of deceleration.