Observation of ocean tides below the Filchner and Ronne Ice Shelves, Antarctica, using synthetic aperture radar interferometry: Comparison with tide model predictions
Observation of ocean tides below the Filchner and Ronne Ice Shelves, Antarctica, using synthetic aperture radar interferometry: Comparison with tide model predictions
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DOI：
10.1029/1999jc000011
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发表时间：
2000-08
影响因子：
--
通讯作者：
E. Rignot;L. Padman;D. Macayeal;M. Schmeltz
中科院分区：
文献类型：
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作者：
E. Rignot;L. Padman;D. Macayeal;M. Schmeltz
在漂浮的冰川附近和下面的潮汐，如峡湾中的冰架和冰川终端，可以影响热量传输到冰下空腔，冰下水柱的混合，以及冰山的崩解和随后的漂移。自由表面位移模式与海洋变化冰川冰下可以观察到的差异两个合成孔径雷达（SAR）干涉图，其中每一个代表的组合与随时间变化的垂直运动和时间无关的横向冰流的位移模式。我们提出的模式净自由面位移的伦讷和Filchner冰架在南部威德尔海的冰山崩解区。通过比较基于SAR的位移场与海洋潮汐模型，这些地区的自由表面位移的变化被发现占主导地位的海洋潮汐。逆气压计效应，即，海洋对大气压力变化的均衡反应也有助于观察到的垂直位移。以这种方式使用合成孔径雷达干涉测量法的主要价值在于在每幅合成孔径雷达图像覆盖的大区域上获得非常高的横向分辨率（数十米）。海洋潮汐模型的典型网格间距不能很好地解决的小特征可能有助于冰山崩解和冰架下海洋空腔的跨锋面通风等过程。
Tides near and under floating glacial ice, such as ice shelves and glacier termini in fjords, can influence heat transport into the subice cavity, mixing of the under-ice water column, and the calving and subsequent drift of icebergs. Free-surface displacement patterns associated with ocean variability below glacial ice can be observed by differencing two synthetic aperture radar (SAR) interferograms, each of which represents the combination of the displacement patterns associated with the time-varying vertical motion and the time-independent lateral ice flow. We present the pattern of net free-surface displacement for the iceberg calving regions of the Ronne and Filchner Ice Shelves in the southern Weddell Sea. By comparing SAR-based displacement fields with ocean tidal models, the free-surface displacement variability for these regions is found to be dominated by ocean tides. The inverse barometer effect, i.e., the ocean's isostatic response to changing atmospheric pressure, also contributes to the observed vertical displacement. The principal value of using SAR interferometry in this manner lies in the very high lateral resolution (tens of meters) obtained over the large region covered by each SAR image. Small features that are not well resolved by the typical grid spacing of ocean tidal models may contribute to such processes as iceberg calving and cross-frontal ventilation of the ocean cavity under the ice shelf.