Penetration depths inferred from interferometric volume decorrelation observed over the Greenland ice sheet
Penetration depths inferred from interferometric volume decorrelation observed over the Greenland ice sheet
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DOI：
10.1109/36.885204
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发表时间：
2000-11-01
影响因子：
8.2
通讯作者：
Zebker, HA
中科院分区：
文献类型：
--
作者：
Hoen, EW;Zebker, HA
雷达干涉测量提供了一种新的方法来研究冰川的地下：干涉相关。由于组成干涉图的两个复杂图像在地面上的每个点处具有略微不同的入射角，因此干涉图中存在与散射介质相关的统计数据的去相关相位噪声。“表面”去相关的量通过体积散射而增加。雷达回波中散射体的垂直范围越大，去相关性就越大。通过模拟这种效应，我们可以估计冰川或冰盖上层的无线电波穿透深度。利用ERS数据对格陵兰冰盖进行观测，得到的穿透深度（单程，功率为1/e点）为12 ~ 35 m。由于体积散射的影响，干涉仪的临界基线降低，对于格陵兰数据，必须将基线限制在300 m以内。我们还比较了渗透深度内的干雪区与渗透区和沿海地区发现的。我们发现，正如预期的那样，岩石海岸地区的证据最小的渗透。有趣的是，渗透深度，我们在渗流区测量，类似于23米，表明了很大程度的体积分散，这是相反的早期结果，发现分散在渗流区占主导地位的结构在最初的几米。这种差异可能是由于未建模的散射行为，或者雷达回波可能确实包括来自地表下很远的散射体的重要贡献。
Radar interferometry provides a novel way to study the subsurface of glaciers: interferometric correlation, Since the two complex images that comprise the interferogram have slightly different incidence angles at each point on the ground, a decorrelating phase noise, with statistics related to the scattering medium, is present in the interferogram. The amount of "surface" decorrelation is increased by volume scatter. The larger the vertical extent of the scatterers contributing to the radar echo, the greater the decorrelation will he, By modeling this effect, we can estimate radio wave penetration depths within the upper layers of the glacier or ice sheet. Observations of the Greenland Ice Sheet using ERS data yield penetration depths (one-way, 1/e point for power) that range from 12 to 35 m, Due to the contribution of volume scatter, the critical interferometer baseline Is decreased, and we find for the Greenland data, the baseline must he restricted to be less than 300 m. We also compare penetration depths measured within the dry snow zone with those found in the percolation zone and coastal areas. We find that as expected, the rocky coastal areas evidence minimal penetration. Interestingly, the penetration depths that we measure In the percolation zone, similar to 23 m, indicate a large degree of volume scatter, which is contrary to earlier results that found the scattering in the percolation zone dominated by structures in the first few meters. This discrepancy may be due to unmodeled scattering behavior, or the radar return may indeed include significant contributions from scatterers far beneath the surface.