Improving the capability of D-InSAR combined with offset-tracking for monitoring glacier velocity
Improving the capability of D-InSAR combined with offset-tracking for monitoring glacier velocity
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提高D-InSAR结合偏移跟踪监测冰川速度的能力
DOI：
10.1016/j.rse.2022.113394
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发表时间：
2023-02
影响因子：
13.5
通讯作者：
Xiao Cheng
中科院分区：
文献类型：
--
作者：
Xiaoman Feng;Zhuoqi Chen;Gang Li;Qi Ju;Zhibing Yang;Xiao Cheng
在格陵兰冰盖（GrIS）冰川速度监测中，偏移跟踪比D-InSAR技术更常用，因为它在处理低相干性和不必要的相位展开的鲁棒性。极地冰川的大变形率会导致变形梯度超过相位展开的理论极限。Sentinel-1干涉图具有可接受的相干性，但传统的D-InSAR在相位展开步骤中仍然失败。在这里，我们提出了一种方法来减少相位梯度的D-InSAR干涉图通过减去估计的变形相位，以获得一个剩余的相位。这种粗略的变形可以通过对当前一对SAR图像进行偏移跟踪来获得，也可以通过任何其他冰川速度产品来计算，这些产品通常是通过偏移跟踪技术获得的。然后对残余相位进行相位展开，然后添加粗变形相位以产生最终变形场。在格陵兰岛北方的四个观测点上，与传统的D-InSAR干涉测量相比，该方法在春、夏、秋、冬四季的剩余相位平均相干性分别提高了0.037、0.032、0.037和0.039。相位梯度的模量也减少，在每个季节分别减少0.054、0.044、0.056和0.064 rad。相干性的改善是更敏感的时间基线在夏季比其他季节，我们的方法是不太有效的。7个冰川相位剖面的解包实验表明，该方法在空间和时间上的相位连续性都优于传统的D-InSAR。在6天的基线期间检测到的最大变形从D-InSAR的1.4 m增加到建议的方法的1.36 m。我们的方法扩展了可以正确展开的区域，特别是对于冰川的下游区域，在那里有较高的流速，反过来，这增加了相位展开的鲁棒性和应用干涉合成孔径雷达方法监测快速移动的冰川在GrIS的可能性。
Offset-tracking is more commonly used in monitoring glacier velocity at Greenland Ice Sheet (GrIS) than the D-InSAR technique because of its robustness in handling low coherence and unnecessary of phase unwrapping. Large deformation rates of polar glaciers can cause a deformation gradient which exceeds the theoretical limitation of phase unwrapping. There is acceptable coherence for Sentinel-1 interferograms with very short temporal baselines, however, traditional D-InSAR still fails at the phase unwrapping step. Here, we propose a method to reduce the phase gradient of the D-InSAR interferogram via subtracting the estimated deformation phase to obtain a residual phase. Such rough deformation can be acquired by performing offset-tracking to the current pair of SAR images or can be calculated by any other glacier velocity products, which are usually obtained by the offset-tracking technique. Phase unwrapping is then performed on the residual phase and then the rough deformation phase is added to yield the final deformation fields. Four study sites located in northern Greenland are selected to test our proposed method, which improved the mean coherence of the residual phase by 0.037, 0.032, 0.037, and 0.039 in spring, summer, autumn, and winter, as compared to traditional D-InSAR interferometry. The modulus of the phase gradient is also reduced, by 0.054, 0.044, 0.056, and 0.064 rad in each season. The coherence improvement is more sensitive to the temporal baseline in summer than other seasons, and our method is less effective. Seven unwrapped phase profiles of the glaciers find that our method performs better in spatial and temporal phase continuity than traditional D-InSAR. The maximum deformation detected during 6-day baseline increases from ∼1.4 m by D-InSAR to ∼3.6 m by the proposed method. Our approach extends the area that can be unwrapped correctly, especially for the downstream zone of glaciers, where there are higher flow rates, in turn, this increases the robustness of the phase unwrapping and the possibility of applying the InSAR method for monitoring fast-moving glaciers in the GrIS.
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影响因子：
13.5
作者：
S. Samsonov;K. Tiampo;R. Cassotto
通讯作者：
S. Samsonov;K. Tiampo;R. Cassotto
影响因子：
5.2
作者：
Enderlin, Ellyn M.;Howat, Ian M.;van den Broeke, Michiel R.
通讯作者：
van den Broeke, Michiel R.
DOI：
10.1109/jstars.2021.3072240
发表时间：
2021
影响因子：
5.5
作者：
Shiyi Li;S. Leinss;I. Hajnsek
通讯作者：
Shiyi Li;S. Leinss;I. Hajnsek
DOI：
10.1073/pnas.1904242116
发表时间：
2019-05-07
影响因子：
11.1
作者：
Mouginot, Jeremie;Rignot, Eric;Wood, Michael
通讯作者：
Wood, Michael
影响因子：
11.4
作者：
A. Solgaard;A. Kusk;J. M. Boncori;J. Dall;K. Mankoff;A. Ahlstrøm;S. Andersen;M. Citterio;N. Karlsson;K. Kjeldsen;N. Korsgaard;S. Larsen;R. Fausto
通讯作者：
A. Solgaard;A. Kusk;J. M. Boncori;J. Dall;K. Mankoff;A. Ahlstrøm;S. Andersen;M. Citterio;N. Karlsson;K. Kjeldsen;N. Korsgaard;S. Larsen;R. Fausto