[논문]Monitoring Time-Series Subsidence Observation in Incheon Using X-Band COSMO-SkyMed Synthetic Aperture Radar

Sang-Hoon Hong

doi:10.7780/kjrs.2024.40.2.2

[국내논문] Monitoring Time-Series Subsidence Observation in Incheon Using X-Band COSMO-SkyMed Synthetic Aperture Radar

대한원격탐사학회지 = Korean journal of remote sensing, v.40 no.2, 2024년, pp.141 - 150

Sang-Hoon Hong (Department of Geological Sciences, Pusan National University)

Abstract ▼ AI-Helper

Ground subsidence in urban areas is mainly caused by anthropogenic factors such as excessive groundwater extraction and underground infrastructure development in the subsurface composed of soft materials. Global Navigation Satellite System data with high temporal resolution have been widely used to measure surface displacements accurately. However, these point-based terrestrial measurements with the low spatial resolution are somewhat limited in observing two-dimensional continuous surface displacements over large areas. The synthetic aperture radar interferometry (InSAR) technique can construct relatively high spatial resolution surface displacement information with accuracy ranging from millimeters to centimeters. Although constellation operations of SAR satellites have improved the revisit cycle, the temporal resolution of space-based observations is still low compared to in-situ observations. In this study, we evaluate the extraction of a time-series of surface displacement in Incheon Metropolitan City, South Korea, using the small baseline subset technique implemented using the commercial software, Gamma. For this purpose, 24 COSMO-SkyMed X-band SAR observations were collected from July 12, 2011, to August 27, 2012. The time-series surface displacement results were improved by reducing random phase noise, correcting residual phase due to satellite orbit errors, and mitigating nonlinear atmospheric phase artifacts. The perpendicular baseline of the collected COSMO-SkyMed SAR images was set to approximately 2-300 m. The surface displacement related to the ground subsidence was detected approximately 1 cm annually around a few Incheon Subway Line 2 route stations. The sufficient coherence indicates that the satellite orbit has been precisely managed for the interferometric processing.

주제어

표/그림 (8)

그림 Fig. 1. Location maps of the study area. (a) Landsat-5 Thematic Mapper high-quality ortho-rectified L1T dataset, which was acquired on 27 Sep 2011, showing the swath of COSMO-SkyMed HIMAGE mode (marked by the red box) utilized in this study. (b) An average amplitude image shows Incheon City near Seoul (Courtesy of United States Geological Survey).
표 Table 1. Parameters of the COSMO-SkyMed datasets used in this study
표 Table 2. The list of interferometric pairs used in the SBAS data processing
표 Table 2. Continued
그림 Fig. 2. Interferometric SAR data pair distribution for the small baseline subset (SBAS) data processing. SAR data acquired on 12 July 2011, was selected as the reference image. The temporal baseline ranges from 16 to 240 days, and the perpendicular baseline is from 1.7 to 299.5 m.
그림 Fig. 3. Schematic diagram of COSMO-SkyMed small subset baseline (SBAS) data processing for surface displacement monitoring in timeseries. All processing procedures have been implemented using Synthetic Aperture Radar PYthon scripts to Retrieve Earth's surface displacements (SARPYRE) developed by Pusan National University.
그림 Fig. 4. Time-series of surface displacement results. (a) The total surface displacement between 12 July 2011, and 27 August 2011. (b) Mean deformation velocity maps. (c) The standard deviation of residual phase for uncertainty analysis. The red box in panel (b) was selected to analyze the time-series of surface displacement in detail.
그림 Fig. 5. Scatter plots of the estimated ground subsidence. (a) A zoomed image showing that surface displacement might be caused by ground subsidence. The white dots marked with (b-f) were selected to examine the pattern of ground subsidence in time-series. (b-f) Plots of time-series of surface displacement at (b-f) in Fig. 4(a). Solid lines represent the linear regression model used to estimate the surface displacement velocity.

AI 본문요약
AI-Helper

제안 방법

Geocoded time-series surface displacement maps were converted into a Google Earth kmz file format to analyze the regional characteristics of the ground subsidence and compare them with existing topographic maps. The five suspected ground subsidence areas are located near Incheon Subway Line 2 or Line 1 stations, suggesting the influence of underground construction associated with subsurface excavation.
This paper conducts the SBAS data processing to detect where surface displacement occurs and further analyzes the characteristics and causes of ground subsidence using the collected COSMO-SkyMed SAR data. To illustrate the study area’s location, the Landsat-5 Thematic Mapper (TM) optical image around Incheon Metropolitan City is shown in Fig.
An automated time-series differential DInSAR script developed by Pusan National University was applied to streamline data processing. This study aims to preliminary analyze possible ground subsidence using high-resolution X-band SAR data temporarily acquired in the early 2010s.
This study constructed a network consisting of 80 interferograms for the SBAS data processing by setting the range of perpendicular baselines from 0 to 300 m and temporal baselines from 1 to 240 days. Fig.

대상 데이터

The COSMO-SkyMed, developed and is being operated in Italy, was launched in June and December 2007, October 2008, and November 2010, with four satellite constellations. The planned mission’s duration was from 2007 to 2019, and they are jointly operated by the ASI and the Italian Ministry of Defence (MoD).
The study area is located in Incheon Metropolitan City on the west coast of South Korea, partially encompassing the southern part of Ganghwa Island and the eastern part of Yeongjong Island. Although the swath width of the collected SAR observation also covers some areas of Seoul, Goyang City, Gimpo City, Bucheon City, Siheung City, and Gwangmyeong City, this study focuses primarily on discussing surface displacement occurred in Incheon Metropolitan City.
The five suspected ground subsidence areas are located near Incheon Subway Line 2 or Line 1 stations, suggesting the influence of underground construction associated with subsurface excavation. The suspected subway stations include Gajeong Jungang Market Station, Gajaeul Station, Jooan National Industrial Complex Station, Inha University Station, and Bupyeong-gu Office Station.

이론/모형

Commercial software Gamma was used for data processing, and Synthetic Aperture Radar PYthon scripts for Retrieval of Earth’s surface displacements (SARPYRE), an automated SBAS data processing script designed and implemented at Pusan National University, was applied
The minimum cost flow (MCF) algorithm was utilized for the phase unwrapping of differential interferograms, and then the phase unwrapping correction procedure was applied. Since each differential interferogram utilizes SAR observations acquired on different dates, inevitable atmospheric artifacts due to water vapor occur.

성능/효과

Thus, more frequent observations are required for the surface displacement analysis in such areas (Hong and Wdowinski, 2013). A shorter revisit cycle through the constellation enables the maximization of InSAR applications of KOMPSAT 6.
In addition, evaluations of possible ground subsidence based on compaction of soft ground materials have been conducted for the Songdo and Cheongna areas of Incheon Metropolitan City (Kim, 2010). According to the literature review, most of the ground subsidence reported in the Incheon Metropolitan City was localized due to the consolidation of facilities resulting from underground structures, and no significant ground subsidence has been reported due to soil compaction in soft ground material.
4(a) illustrates the cumulative surface displacement occurring from July 12, 2011, to August 27, 2012, with a displacement range of –1 to 1 cm. Areas such as water bodies, forests, and intertidal flats were masked in the time-series of surface displacement due to difficulties in maintaining high coherence. The masking process used a threshold of 0.
Considering that Incheon Subway Line 2 opened in July 2016, the surface displacement observed in this study from July 2011 to August 2012 is interpreted as reflecting ground subsidence occurring during that subway construction period. In future work, further analysis is needed to determine if the observed ground subsidence is still ongoing.
Moreover, despite being a short-wavelength X-band SAR, it allows for generating high-resolution interferograms with relatively low temporal decorrelation. In the initial operation, three observation modes, Spotlight, Stripmap, and ScanSAR, were supported, and a wide swath mode was added later to enhance ship monitoring capabilities at sea. The swath covers from 10 to 2,000 km, and there are differences in spatial resolution depending on the observation mode.
In the overall results, most surface displacement was observed locally around urban areas; however, significant subsidence was not observed over widespread study areas. Although localized ground uplift was detected in Fig.
In this study, a time-series ground subsidence analysis has been successfully conducted for the Incheon Metropolitan City using high-resolution COSMO-SkyMed X-band SAR observations acquired over approximately one year, from July 2011 to August 2012. The SARPYRE software, developed by Busan National University to efficiently process numerous SAR datasets, was used for the SBAS data processing.
Since each differential interferogram utilizes SAR observations acquired on different dates, inevitable atmospheric artifacts due to water vapor occur. In this study, an effective reduction of atmospheric artifacts was achieved by applying spatial filters to suppress localized random phase components. The estimated surface displacement through the SVD solver was geocoded using DEM data and exported into Google Earth format for visual analysis.
Korean Multi-Purpose Satellite (KOMPSAT) 5, which is currently operational in South Korea, and KOMPSAT 6, which is nearing completion and scheduled for launch, are designed with the same microwave frequency as the COSMO-SkyMed X-band SAR data used. It implies the potential capability of interferometric SAR techniques in urban areas with frequent data acquisition due to the revisit cycle of KOMPSAT 6 every 11 days. However, coherence significantly degrades in densely forested areas or regions with frequent surface changes like intertidal flats.
Due to significantly shorter revisit cycles, the constellation of the COSMO-SkyMed is a valuable resource for monitoring surface displacements, such as volcanoes, earthquakes, and glaciers. Moreover, despite being a short-wavelength X-band SAR, it allows for generating high-resolution interferograms with relatively low temporal decorrelation. In the initial operation, three observation modes, Spotlight, Stripmap, and ScanSAR, were supported, and a wide swath mode was added later to enhance ship monitoring capabilities at sea.
4(b). Moreover, the scatter plots of the time-series surface displacement analysis indicate no consistent uplift, suspecting the presence of localized atmospheric artifacts or residual phase noise in the short wavelength X-band SAR observations. This localized ground uplift will be investigated further through additional experiments with longer-period datasets in future studies.
No potential conflict of interest relevant to this article was reported.
The subsidence rates observed in the five regions indicate gradual downward surface displacement, reflecting surface displacement velocities corresponding to an annual subsidence of approximately 1 cm. Statistical analysis of time series surface displacement reveals relatively small phase standard deviation levels compared to linear model regression, indicating relatively linear surface displacement trends.
The global TanDEM-X SAR observations were collected entirely in 2015, and the global TanDEM-X DEM production was completed in September 2016 after precise data processing. The absolute height accuracy of the DEM is approximately 1 m, showing better performance than the mission requirement of 10 m.
Geocoded time-series surface displacement maps were converted into a Google Earth kmz file format to analyze the regional characteristics of the ground subsidence and compare them with existing topographic maps. The five suspected ground subsidence areas are located near Incheon Subway Line 2 or Line 1 stations, suggesting the influence of underground construction associated with subsurface excavation. The suspected subway stations include Gajeong Jungang Market Station, Gajaeul Station, Jooan National Industrial Complex Station, Inha University Station, and Bupyeong-gu Office Station.
The COSMO-SkyMed satellites with four-satellite constellation operation can mitigate the coherence degradation due to temporal decorrelation for interferometric applications. The minimum temporal baseline selected for interferogram generation was 16 days for the SBAS processing in this study. Although interferometric pairs with longer temporal baselines were also used, sufficient coherence was observed within urban areas.
This study only focuses on analyzing ground subsidence to interpret regional characteristics. The overall phase standard deviation converging to zero indicates that the SBAS data processing with a high confidence level was achieved.
5(b-f) presents plots of time-series of surface displacement for the selected regions to examine the temporal evolution of the ground subsidence, along with linear regression equations for each plot. The subsidence rates observed in the five regions indicate gradual downward surface displacement, reflecting surface displacement velocities corresponding to an annual subsidence of approximately 1 cm. Statistical analysis of time series surface displacement reveals relatively small phase standard deviation levels compared to linear model regression, indicating relatively linear surface displacement trends.
Although interferometric pairs with longer temporal baselines were also used, sufficient coherence was observed within urban areas. This indicates that time-series surface displacement extraction with a 16-day interval is achievable through precise orbit adjustment and attitude control. Korean Multi-Purpose Satellite (KOMPSAT) 5, which is currently operational in South Korea, and KOMPSAT 6, which is nearing completion and scheduled for launch, are designed with the same microwave frequency as the COSMO-SkyMed X-band SAR data used.
Commercial software Gamma was used for data processing, and Synthetic Aperture Radar PYthon scripts for Retrieval of Earth’s surface displacements (SARPYRE), an automated SBAS data processing script designed and implemented at Pusan National University, was applied. Using this automated script of the SARPYRE ensures consistent and effective production of results compared to manual data processing. To subtract the topographic phase, a 90 m spatial resolution of TanDEM-X global DEM was resampled with a 4 × 4 oversampling factor, and multi-looking processing was applied using 4 × 4 multi-looking factors to remove phase noise in the differential interferograms.

후속연구

According to the feasibility reassessment report of Incheon Subway Line 2 conducted by the Korea Development Institute in 2008, the construction of Incheon Subway Line 2 was pursued to alleviate urban traffic congestion caused by the Geomdan New Town, the Yeongjong-Cheongna Economic Free Zone development projects. Another purpose of the construction project is to alleviate traffic congestion by partially connecting the north-south and east-west axes of Incheon Metropolitan City, induce pollution reduction, and balance regional development. The initial planned construction period was from 2007 to 2013, but construction began in June 2009 and was not opened until July 30, 2016.
These preliminary results can serve as an initial analysis indicating ground subsidence patterns according to the distribution of Incheon subway routes. Furthermore, a comparison study of surface displacement changes before and after subway completion can be worth investigating using long-term multi-temporal SAR data such as the European Sentinel-1 satellite data.
Considering that Incheon Subway Line 2 opened in July 2016, the surface displacement observed in this study from July 2011 to August 2012 is interpreted as reflecting ground subsidence occurring during that subway construction period. In future work, further analysis is needed to determine if the observed ground subsidence is still ongoing. These preliminary results can serve as an initial analysis indicating ground subsidence patterns according to the distribution of Incheon subway routes.
Locally observed ground uplift is interpreted as undesirable noise due to atmospheric artifacts commonly found in interferograms with short SAR wavelength bands. More precise time-series ground subsidence analysis would be required in the near future, utilizing long-term European Sentinel-1 SAR data collected before and after the completion of Incheon Subway Line 2.
Moreover, the scatter plots of the time-series surface displacement analysis indicate no consistent uplift, suspecting the presence of localized atmospheric artifacts or residual phase noise in the short wavelength X-band SAR observations. This localized ground uplift will be investigated further through additional experiments with longer-period datasets in future studies. This study only focuses on analyzing ground subsidence to interpret regional characteristics.

참고문헌 (26)

Abidin, H. Z.,Andreas, H., Djaja, R., Darmawan, D., and Gamal,？M., 2008. Land subsidence characteristics of Jakarta？between 1997 and 2005, as estimated using GPS surveys.？Gps Solutions, 12, 23-32. https://doi.org/10.1007/s10291-007-0061-0？

상세보기
Berardino, P., Fornaro, G., Lanari, R., and Sansosti, E., 2002. A？New algorithm for surface deformation monitoring based？on small baseline differential SAR interferograms. IEEE？Transactions on Geoscience and Remote Sensing, 40(11),？2375-2383. https://doi.org/10.1109/TGRS.2002.803792？

상세보기
Bruno, M., 1992. Subsidence-induced well failure. SPE Drilling？Engineering, 7(2), 148-152. https://doi.org/10.2118/20058-PA？

상세보기
Fattahi, H., Simons, M., and Agram, P., 2017. InSAR time-series？estimation of the ionospheric phase delay: An extension？of the split range-spectrum technique. IEEE Transactions？on Geoscience and Remote Sensing, 55(10), 5984-5996.？https://doi.org/10.1109/TGRS.2017.2718566？

상세보기
Ferretti, A., Prati, C., and Rocca, F., 2001. Permanent scatterers？in SAR interferometry. IEEE Transactions on Geoscience？and Remote Sensing, 39(1), 8-20. https://doi.org/10.1109/36.898661？

상세보기
Gabriel, A. K., Goldstein, R. M., andZebker, H. A., 1989.Mapping？small elevation changes overlarge areas: Differential radar？interferometry. Journal of Geophysical Research: Solid？Earth, 94(B7), 9183-9191. https://doi.org/10.1029/JB094iB07p09183？

상세보기
Goldstein, R. M., and Werner, C. L., 1998. Radar interferogram？filtering for geophysical applications. Geophysical Research？Letters, 25, 4035-4038. https://doi.org/10.1029/1998GL900033？

상세보기
Hanssen, R. F., 2001. Radar interferometry: Data interpretation？and error analysis(Vol. 2). Springer Science and Business？Media. https://doi.org/10.1007/0-306-47633-9？
Hong, S.-H., 2019. Parallel computing on intensity offset tracking？using synthetic aperture radar for retrieval of glacier？velocity. Korean Journal of Remote Sensing, 35(1), 29-37.？https://doi.org/10.7780/kjrs.2019.35.1.3？

원문보기 상세보기
Hong, S.-H., and Wdowinski, S., 2013. Multitemporal multitrack？monitoring of wetland water levels in the Florida Everglades？usingALOSPALSARdatawith interferometric processing.？IEEE Geoscience and Remote Sensing Letters, 11(8), 1355-1359. https://doi.org/10.1109/LGRS.2013.2293492？

상세보기
Hong, S.-H., Wdowinski, S., and Kim, S.-W., 2009. Evaluation of？TerraSAR-X observations for wetland InSAR application.？IEEE Transactions on Geoscience and Remote Sensing,？48(2), 864-873. https://doi.org/10.1109/TGRS.2009.2026895？

상세보기
Hong, S.-H., Wdowinski, S., Kim, S.-W., and Won, J.-S., 2010.？Multi-temporal monitoring of wetland water levelsin the？Florida Everglades using interferometric synthetic aperture？radar (InSAR). Remote Sensing of Environment, 114(11),？2436-2447. https://doi.org/10.1016/j.rse.2010.05.019？

상세보기
Jolivet, R., Grandin, R., Lasserre, C., Doin, M. P., and Peltzer,？G., 2011. Systematic InSAR tropospheric phase delay？corrections from global meteorological reanalysis data.？Geophysical Research Letters, 38(17). https://doi.org/10.1029/2011GL048757？

상세보기
Jung, H.-S., Lee, D.-T., Lu, Z., and Won, J.-S., 2012. Ionospheric？correction of SAR interferograms by multiple-aperture？interferometry. IEEE Transactions on Geoscience and？Remote Sensing, 51(5), 3191-3199. https://doi.org/10.1109/TGRS.2012.2218660？

상세보기
Kampes, B. M., 2006. Radar interferometry (Vol. 12). Springer.
Kim, D. H., Bae, K. D., Ko, S. K., and Lee, W. J., 2010. Evaluation？of spatial distribution of secondary compression of Songdo marine clay by probabilistic method. Journal of the Korean？Geotechnical Society, 26(9), 25-35. https://doi.org/10.7843/kgs.2010.26.9.25？

원문보기 상세보기
Kim, E.K., 2018. Policy suggestions for the creation of a safe road？environment in Incheon City: Focused on measures for？the ground settlement management. Korean Journal of？Urban Studies, 13, 79-106. https://doi.org/10.34165/urbanr.2018..13.79？
Kim, S.-W., Wdowinski, S., Amelung, F., Dixon, T. H., and Won,？J.-S., 2013. Interferometric coherence analysis of the？Everglades wetlands, South Florida. IEEE Transactions？on Geoscience and Remote Sensing, 51(12), 5210-5224.？https://doi.org/10.1109/TGRS.2012.2231418？

상세보기
Massonnet, D., and Feigl, K. L., 1998. Radar interferometry and？its application to changes in the Earth's surface. Reviews？of Geophysics, 36(4), 441-500. https://doi.org/10.1029/97RG03139？

상세보기
Milliman, J. D., and Haq, B. U., 1996. Sea-level rise and coastal？subsidence: Causes, consequences, and strategies (Vol. 2).？Springer Science and Business Media.？
Moreira, A., Prats-Iraola, P., Younis, M., Krieger, G., Hajnsek, I.,？and Papathanassiou, K. P., 2013. A tutorial on synthetic？aperture radar. IEEE Geoscience and Remote Sensing？Magazine, 1(1), 6-43. https://doi.org/10.1109/MGRS.2013.2248301？

상세보기
Park, S. W., and Hong, S. H., 2021. Nonlinear modeling of？subsidence from a decade of InSAR time-series. Geophysical？Research Letters, 48(3), e2020GL090970. https://doi.org/10.1029/2020GL090970？

상세보기
Rosen, P. A., Hensley, S., Joughin, I. R., Li, F. K., Madsen, S. N.,？Rodriguez, E., and Goldstein, R. M., 2000. Synthetic？aperture radar interferometry. Proceedings of the IEEE,？88(3), 333-382. https://doi.org/10.1109/5.838084？

상세보기
Wessel, B., Huber, M.,Wohlfart, C., Marschalk, U., Kosmann, D.,？and Roth, A., 2018. Accuracy assessment of the global？TanDEM-X Digital Elevation Model with GPS data.？ISPRS Journal of Photogrammetry and Remote Sensing,？139, 171-182. https://doi.org/10.1016/j.isprsjprs.2018.02.017？

상세보기
Wright, T. J., Parsons, B. E., and Lu, Z., 2004. Toward mapping？surface deformation in three dimensions using InSAR.？Geophysical Research Letters, 31(1). https://doi.org/10.1029/2003GL018827？

상세보기
Zebker, H. A., Rosen, P. A., Goldstein, R. M., Gabriel, A., and？Werner, C. L., 1994. On the derivation of coseismic？displacement fields using differential radar interferometry:？The Landers earthquake. Journal of Geophysical Research:？Solid Earth, 99(B10), 19617-19634. https://doi.org/10.1029/94JB01179？

상세보기

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