PS-InSAR Analysis of Sentinel-1 Data for Detecting Ground Motion in Temperate Oceanic Climate Zones: A Case Study in the Republic of Ireland

Abstract

Regions of temperate oceanic climate have historically represented a challenge for the application of satellite-based multi-temporal SAR interferometry. The landscapes of such regions are commonly characterized by extensive, seasonally-variable vegetation coverage that can cause low temporal coherence and limit the detection capabilities of SAR imagery as acquired, for instance, by previous ERS-1/2 and ENVISAT missions. In this work, we exploited the enhanced resolution in space and time of the recently deployed Sentinel-1A/B SAR satellites to detect and monitor ground motions occurring in two study areas in the Republic of Ireland. The first, is a~1800 km 2 area spanning the upland karst of the Clare Burren and the adjacent mantled lowland karst of east Galway. The second, is an area of 100 km 2 in Co. Meath spanning an active mine site. The available datasets, consisting of more than 100 images acquired in both ascending and descending orbits from April 2015 to March 2018, were processed by using the Permanent Scatterer approach. The obtained results highlight the presence of small-scale ground motions in both urban and natural environments with displacement rates along the satellite line of sight up to −17 mm/year. Localized subsidence was detected in recently built areas, along the infrastructure (both roads and railways), and over the mine site, while zones of subsidence, uplift, or both, have been recorded in a number of peatland areas. Furthermore, several measured target points indicate the presence of unstable areas along the coastline. Many of the detected movements were previously unknown. These results demonstrate the feasibility of adopting multi-temporal interferometry based on Sentinel-1 data for the detection and monitoring of mm-scale ground movements even over small areas (<100 m 2 ) in environments influenced by temperate oceanic climate.

InSAR Time Series Analysis of L-Band Data for Understanding Tropical Peatland Degradation and Restoration

“…In this study, a coherence threshold of 0.3 and a recurrence of 50% in all interferograms strategy is applied, the final partially coherent pixels covers 62% of the study area. In addition, using C-band data and PS-InSAR method, only 333 stable PS points are found in 6 km 2 boreal peatlands (~56 PS points /km 2 ), where vegetation is dominated by moss [32].Therefore less stable PS points per km 2 are excepted for C-band in tropical peatlands.…”

“…Using 161 Sentinel-1 SAR (C-band) images and ISBAS method, Marshall et al, [24] also measured the deformation patterns of tropical peat swamp around Kuala Lumpur International Airport. Fiaschi et al, [32] detected uplift signal of up to 8.9 mm/year and subsidence signal of up to −11.6 mm/year in Irish peatlands by using 124 Sentinel-1A/B images acquired from 4 May 2015 to 1 March 2018 and PS-InSAR method. Although, C-band shows potential in measuring peatlands surface motion, it is likely hard to extract sufficient number of PS points and provide good coverage, particularly over a tropical peatlands area [24].…”

A Novel Low-Cost, High-Resolution Camera System for Measuring Peat Subsidence and Water Table Dynamics

“…Evidence that peat vertical motion is related to climate and management raises the possibility that it could be used as an effective, and easily measured, proxy for key metrics of peat condition such as water table depth (WTD) and carbon balance, as well as a tool for evaluating restoration outcomes. A number of recent studies have also suggested that this surface motion can be detected remotely using Interferometric Synthetic Aperture Radar (InSAR) data from satellites such as the European Space Agency's Sentinel-1 mission, and the Japan Aerospace Exploration Agency's Advanced Land Observation Satellite-1 (ALOS-1) (Alshammari et al, 2018;Fiaschi et al, 2019;Marshall et al, 2018;Susanti and Anjasmara, 2019;Zhou et al, 2019;Hoyt et al, 2020). This approach offers clear advantages in terms of the cost, spatial scale and frequency at which information can be obtained, especially for large and remote peatland areas.…”

Feasibility of Artificial Slope Hazards Identification in Regional Mountainous Highway Using SBAS-InSAR Technique: A Case Study in Lishui, Zhejiang

“…As limited by the spatial displacement gradient, the InSAR is normally suitable for detection of slow(13 m/month) to extremely-slow (<16 mm/yr) movement [21]. Commonly used MT-InSAR techniques include PS-InSAR (Persistent Scatterer Interferometry) [22][23][24][25] and SBAS-InSAR [26][27][28][29]. The PS-InSAR method obtains long-term series of ground deformation at the expense of the density of monitoring points in space.…”