College of Earth Sciences, Chengdu University of Technology, Chengdu 610059, China.
State Key Laboratory of Geohazard Prevention and Geoenviroment Protection, Chengdu University of Technology, Chengdu 610059, China.
Sensors (Basel). 2018 Jun 8;18(6):1876. doi: 10.3390/s18061876.
Interferograms with short wavelength (e.g., X-band) are usually prone to temporal decorrelation in permafrost regions, leading to the unavailability of sufficient high-coherence interferograms for performing conventional time series InSAR analysis. This paper proposes the utilization of temporary scatterers for the stacking InSAR method, thus enabling extraction of subsidence in a permafrost region with limited SAR images and limited high-coherence interferograms. Such method is termed as the temporary scatterers stacking InSAR (TSS-InSAR). Taking the Gonghe-Yushu highway (about 30 km), part of G214 National Highway in Qinghai province (in a permafrost region), as a case study, this TSS-InSAR approach was demonstrated in detail and implemented. With 10 TerraSAR-X images acquired during the period from May 2015 to August 2015, the subsidence along this highway was extracted. In this case the lack of a consistent number of SAR acquisitions limits the possibility to perform other conventional time series InSAR analysis. The results show that the middle part of this highway is in the thermokarst and seasonal frozen soil area, and its accumulated subsidence reach up to 10 cm in 110 days. The thawing phenomena is still the main reason for the instability of highway. The results demonstrate that the TSS-InSAR method can effectively extract the subsidence information in a challenging scenario with limited X-band SAR images and limited high-coherence interferograms, where other time series InSAR-based techniques cannot be applied in a simple way.
在多年冻土区，短波长（如 X 波段）的干涉条纹通常容易出现时间去相关，导致无法获得足够多的高相干干涉条纹来进行传统的时间序列 InSAR 分析。本文提出了利用临时散射体进行堆叠 InSAR 方法，从而能够在 SAR 图像和高相干干涉条纹有限的多年冻土区提取沉降。这种方法被称为临时散射体堆叠 InSAR（TSS-InSAR）。以青海省 214 国道共和至玉树段（约 30 公里）为例，详细介绍并实施了这种 TSS-InSAR 方法。利用 2015 年 5 月至 8 月期间获取的 10 景 TerraSAR-X 图像，提取了这条公路沿线的沉降。在这种情况下，缺乏一致数量的 SAR 采集限制了执行其他传统时间序列 InSAR 分析的可能性。结果表明，这条公路的中部处于热喀斯特和季节性冻土区，在 110 天内累计沉降达到 10 厘米。融冻现象仍然是公路不稳定的主要原因。结果表明，TSS-InSAR 方法可以有效地提取具有挑战性的场景中的沉降信息，这些场景的 X 波段 SAR 图像和高相干干涉条纹有限，其他基于时间序列 InSAR 的技术无法简单地应用。
