Long-Term Peatland Condition Assessment via Surface Motion Monitoring Using the ISBAS DInSAR Technique over the Flow Country, Scotland
Long-Term Peatland Condition Assessment via Surface Motion Monitoring Using the ISBAS DInSAR Technique over the Flow Country, Scotland
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DOI：
10.3390/rs10071103
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发表时间：
2018-07
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通讯作者：
Lubna Alshammari;D. Large;D. Boyd;A. Sowter;Russell Anderson;R. Andersen;S. Marsh
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作者：
Lubna Alshammari;D. Large;D. Boyd;A. Sowter;Russell Anderson;R. Andersen;S. Marsh
卫星地球观测（EO）通常被用作一种具有成本效益的方法，以报告偏远和难以进入的泥炭地地区的状况。目前的EO技术主要局限于使用光学数据报告直接泥炭表面的植被类别和属性，可用于推断泥炭地状况。泥炭地状况的另一个有用指标是地表运动，它有可能报告泥炭的质量积累和损失。干涉合成孔径雷达（干涉合成孔径雷达）技术可以利用空间数据提供这一点。然而，用于信息提取的最常见的干涉合成孔径雷达技术，如持续散射体干涉测量法（PSI），在泥炭上的应用有限，因为它们主要用于高相干性区域（即，仅在硬的、无植被的表面上）。一种新的干涉合成孔径雷达技术，称为间歇小基线子集（ISBAS）的方法，最近已经开发出来，提供测量植被地区从卫星传感器获得的SAR数据。本文探讨了ISBAS技术的可行性，用于监测长期的表面运动在泥炭地地区的流动的国家，在苏格兰东北部。特别是，估计的表面运动与地面数据进行比较，在一个小的森林面积（即坏的Cheo森林保护区）。使用了两组卫星合成孔径雷达数据：1992-2000年期间的ERS C波段图像和2015-2016年期间的Sentinel-1 C波段图像。我们表明，ISBAS测量能够识别泥炭地地区的地表运动，沉降是已知的土地覆盖/土地利用的结果。特别是，ISBAS产品与地面运动的趋势一致，但其幅度和方向（垂直）存在不确定性。它的结论是，有一个潜在的ISBAS方法能够报告的趋势，在泥炭地地区的沉降和隆起，本文提出了进一步调查的途径，但这需要一个资源充足的验证活动。
Satellite Earth Observation (EO) is often used as a cost-effective method to report on the condition of remote and inaccessible peatland areas. Current EO techniques are primarily limited to reporting on the vegetation classes and properties of the immediate peat surface using optical data, which can be used to infer peatland condition. Another useful indicator of peatland condition is that of surface motion, which has the potential to report on mass accumulation and loss of peat. Interferometic SAR (InSAR) techniques can provide this using data from space. However, the most common InSAR techniques for information extraction, such as Persistent Scatterers’ Interferometry (PSI), have seen limited application over peat as they are primarily tuned to work in areas of high coherence (i.e., on hard, non-vegetated surfaces only). A new InSAR technique, called the Intermittent Small BAseline Subset (ISBAS) method, has been recently developed to provide measurements over vegetated areas from SAR data acquired by satellite sensors. This paper examines the feasibility of the ISBAS technique for monitoring long-term surface motion over peatland areas of the Flow Country, in the northeast of Scotland. In particular, the surface motions estimated are compared with ground data over a small forested area (namely the Bad a Cheo forest Reserve). Two sets of satellite SAR data are used: ERS C-band images, covering the period 1992–2000, and Sentinel-1 C-band images, covering the period 2015–2016. We show that the ISBAS measurements are able to identify surface motion over peatland areas, where subsidence is a consequence of known land cover/land use. In particular, the ISBAS products agree with the trend of surface motion, but there are uncertainties with their magnitude and direction (vertical). It is concluded that there is a potential for the ISBAS method to be able to report on trends in subsidence and uplift over peatland areas, and this paper suggests avenues for further investigation, but this requires a well-resourced validation campaign.