Changes in the dynamics of marine terminating outlet glaciers in west Greenland (2000–2009)
Changes in the dynamics of marine terminating outlet glaciers in west Greenland (2000–2009)
复制标题
格陵兰岛西部海洋终止出口冰川动态变化（2000-2009）
DOI：
10.1029/2010jf001757
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发表时间：
2011
影响因子：
--
通讯作者：
Y. Ahn
中科院分区：
文献类型：
--
作者：
E. M. McFadden;I. Howat;I. Joughin;Ben E. Smith;Y. Ahn
[1]格陵兰海洋终端出口冰川动态的最新变化表明了对外部强迫的快速而复杂的反应。尽管观测到的冰锋退缩和最近的地球物理证据表明，格陵兰岛西北边缘的质量损失沿着加速，但尚不清楚西格陵兰冰川是否经历了本世纪初在东南部冰川观察到的同步加速和随后的减速。为了研究西格陵兰出口冰川动态的变化及其行为背后的潜在控制因素，我们推导了2000年至2009年西格陵兰59个海洋终端出口冰川的前沿位置，表面高程和表面坡度以及选择冰川的表面速度的时间序列。利用这些数据，我们寻找退缩，变薄，加速度和几何参数之间的关系，以确定一阶控制冰川行为。我们的数据表明，在每年的时间尺度上，前沿位置和表面海拔的变化是异步的，虽然几乎所有的冰川退缩和变薄了十年。我们没有发现后退、加速和适用于整个地区的外部强迫之间有直接的关系。在几何学方面，我们发现，在退缩之后，（1）与浮动终端相比，终端接地的冰川经历了更明显的动态变化，（2）坡度较陡的冰川变薄速率下降得更快。总体而言，冰川的几何形状应影响出口冰川动力学通过应力重新分配后，在前面的扰动，但我们的数据表明，相对重要的几何形状作为控制冰川的行为是高度可变的整个西格陵兰岛。
[1] Recent changes in the dynamics of Greenland's marine terminating outlet glaciers indicate a rapid and complex response to external forcing. Despite observed ice front retreat and recent geophysical evidence for accelerated mass loss along Greenland's northwestern margin, it is unclear whether west Greenland glaciers have undergone the synchronous speed-up and subsequent slow-down as observed in southeastern glaciers earlier in the decade. To investigate changes in west Greenland outlet glacier dynamics and the potential controls behind their behavior, we derive time series of front position, surface elevation, and surface slope for 59 marine terminating outlet glaciers and surface speeds for select glaciers in west Greenland from 2000 to 2009. Using these data, we look for relationships between retreat, thinning, acceleration, and geometric parameters to determine the first-order controls on glacier behavior. Our data indicate that changes in front positions and surface elevations were asynchronous on annual time scales, though nearly all glaciers retreated and thinned over the decade. We found no direct relationship between retreat, acceleration, and external forcing applicable to the entire region. In regard to geometry, we found that, following retreat, (1) glaciers with grounded termini experienced more pronounced changes in dynamics than those with floating termini and (2) thinning rates declined more quickly for glaciers with steeper slopes. Overall, glacier geometry should influence outlet glacier dynamics via stress redistribution following perturbations at the front, but our data indicate that the relative importance of geometry as a control of glacier behavior is highly variable throughout west Greenland.