Surface melt and ponding on Larsen C Ice Shelf and the impact of fohn winds
Surface melt and ponding on Larsen C Ice Shelf and the impact of fohn winds
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DOI：
10.1017/s0954102014000339
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发表时间：
2014-12-01
影响因子：
1.6
通讯作者：
Barrand, Nicholas E.
中科院分区：
文献类型：
--
作者：
Luckman, Adrian;Elvidge, Andrew;Barrand, Nicholas E.
冰架解体的一个常见前兆，最明显的是拉森B冰架，是异常强烈或长时间的地表融化和地表死水的存在。然而，对冰架上融化的详细模式或夏季融化池的性质的研究很少。利用Envisat先进合成孔径雷达（ASAR）数据对Larsen C冰架的表面融化进行了高分辨率研究，并利用一系列卫星图像探索了融化池。与其他方法相比，SAR空间分辨率的提高揭示了西部入口异常长的融化持续时间。气象模型用该地区常见的焚风来解释这种模式。由于该地区很少有无云的条件，因此很难使用光学图像检测融化池，并且融化池很快就会结冰，但可以在所有天气条件下使用SAR进行监测。长达数十公里的熔体池在Cabinet Inlet很常见，那里的熔体持续时间最长。融化的模式解释了先前观察到的冰架密度分布，部分地区已经达到拉森B冰架崩塌之前的水平，这表明风在促进冰架不稳定状况方面的潜在作用。
A common precursor to ice shelf disintegration, most notably that of Larsen B Ice Shelf, is unusually intense or prolonged surface melt and the presence of surface standing water. However, there has been little research into detailed patterns of melt on ice shelves or the nature of summer melt ponds. We investigated surface melt on Larsen C Ice Shelf at high resolution using Envisat advanced synthetic aperture radar (ASAR) data and explored melt ponds in a range of satellite images. The improved spatial resolution of SAR over alternative approaches revealed anomalously long melt duration in western inlets. Meteorological modelling explained this pattern by fohn winds which were common in this region. Melt ponds are difficult to detect using optical imagery because cloud-free conditions are rare in this region and ponds quickly freeze over, but can be monitored using SAR in all weather conditions. Melt ponds up to tens of kilometres in length were common in Cabinet Inlet, where melt duration was most prolonged. The pattern of melt explains the previously observed distribution of ice shelf densification, which in parts had reached levels that preceded the collapse of Larsen B Ice Shelf, suggesting a potential role for fohn winds in promoting unstable conditions on ice shelves.