Integration PS-InSAR and MODIS PWV Data to Monitor Land Subsidence in Semarang City 2015–2018

Abstract

Land Subsidence is a slow on set disaster that can be found in coastal areas such as Semarang City. The cause is changing natural conditions and human activities. The observation method that is often done for this phenomenon is GNSS observation. The GNSS observations do not cover the entire area are the disadvantages of this method. Solution that can be used is to use a multi-temporal Interferometric Synthetic Aperture Radar (InSAR) method called Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR). In its application, PS-InSAR has a problem in the form of tropospheric errors that cause signal interference on SAR sensors when making acquisitions that contained in every Synthetic Aperture Radar (SAR) image. MODIS with the NIR band provide Precipitable Water Vapor (PWV) to estimate water vapor levels in the atmosphere. This component can be used in the PS-InSAR in order to eliminate the tropospheric effect on each image so that errors can be minimized and optimize the work of the PS-InSAR method. Based on the value of PS-InSAR before and after tropospheric correction, it is known that the area of Semarang City experienced a rate of land subsidence and the rate of uplift. Land subsidence rate occurs along the northern region, northeast to the east of Semarang City. Uplift rate only occurs in the southeast region due to dumping excavation activities for development and Banjir Kanal Barat due to the river revitalization process. Overall, Semarang City has experienced a land subsidence from 0 to 6.753 cm/year.

Progress or Regress? A Systematic Review on Two Decades of Monitoring and Addressing Land Subsidence Hazards in Semarang City

“…The most severe land subsidence rates were reported in the northeastern part of the coastal area in Semarang [35,[57][58][59][60][61][62][63][64][65]. According to the spatial estimation, land subsidence occurs in 32.92% of the city area, which is about 128.65 km 2 [66].…”

“…Land subsidence might cause Semarang to lose its coastal areas in the future [27,85,109]. Land value decrease [122] Property value decrease [114] Disruption in economic activities [62,114] Worsening Social Quality of life Lowering quality of life [8,19,58,70,72,76,119] Disrupting local people's day-to-day activity [26,41,65,114,123,124] Increasing coastal vulnerability [2,5] Increasing harmful sanitation-related diseases such as Malaria, Dengue, Labtoferosis, etc. [31,52,124,125] Towards the city center, it has caused damage to buildings and streets and degraded people's quality of life.…”

“…We are sending our appreciation to the anonymous reviewers and proofreaders that has given substantial influence on the improvement of this manuscript. [1,2,4,22,41,50,52,53,[56][57][58][59][61][62][63][64][65][66][67][68]70,74,[77][78][79][80][81][82]88,89,148].…”

A New Weighting Method by Considering the Physical Characteristics of Atmospheric Turbulence and Decorrelation Noise in SBAS-InSAR

“…To reduce the effect of atmospheric turbulence, various external meteorological datasets, such as Medium Resolution Imaging Spectrometer (MERIS), Moderate Resolution Imaging Spectroradiometer (MODIS), Global Positioning System (GPS) and the European Centre for Medium-Range Weather Forecast's (ECMWF) Re-Analysis Iterim (ERA-I), have been used in SBAS-InSAR [24][25][26][27]. Azeriansyah used the spectrometer correction method with MODIS PWV products to correct the atmospheric delay and monitor land subsidence in Semarang city [28]. Moreover, Xu pointed out that a combined used of ScanSAR and MODIS PWV can be effectively expanded using the InSAR application scope [29].…”