Grounding line variability and subglacial lake drainage on Pine Island Glacier, Antarctica
Grounding line variability and subglacial lake drainage on Pine Island Glacier, Antarctica
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DOI：
10.1002/2016gl070259
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发表时间：
2016-09-01
影响因子：
5.2
通讯作者：
Dutrieux, P.
中科院分区：
文献类型：
--
作者：
Joughin, Ian;Shean, David E.;Dutrieux, P.
利用TerraSAR-X高分辨率数据，利用斑点跟踪方法，获得了南极洲松岛冰架近6年的潮汐位移时间序列。这些结果表明，主接地线在过去6年中保持了相对稳定的位置，在类似于2009年终止的加速之后。在大陆架中部，有接地点，在6年的记录中向下游迁移。高分辨率数字高程模型的检查表明，这些接地点形成深龙骨（厚度异常）平流超过一个近似流动平行的测深高，保持间歇性接触的床。这些数据集还揭示了几个沉降和隆起事件与冰下湖泊排水在快速流动的区域以上的接地线。虽然这些排水在几周内使冰下水流的速度增加了一倍，但它们对水平流速没有明显的影响。
We produced a 6year time series of differential tidal displacement for Pine Island Ice Shelf, Antarctica, using speckle-tracking methods applied to fine-resolution TerraSAR-X data. These results reveal that the main grounding line has maintained a relatively steady position over the last 6years, following the speedup that terminated in similar to 2009. In the middle of the shelf, there are grounded spots that migrate downstream over the 6year record. Examination of high-resolution digital elevation models reveals that these grounded spots form where deep keels (thickness anomalies) advect over an approximately flow-parallel bathymetric high, maintaining intermittent contact with the bed. These data sets also reveal several subsidence and uplift events associated with subglacial lake drainages in the fast-flowing region above the grounding line. Although these drainages approximately double the rate of subglacial water flow over periods of a few weeks, they have no discernible effect on horizontal flow speed.