Integration PS-InSAR and MODIS PWV Data to Monitor Land Subsidence in Semarang City 2015–2018
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.
 Dahuri, R. (2001). Pengelolaan ruang wilayah pesisir dan lautan seiring dengan pelaksanaan otonomi daerah, Mimbar: Jurnal Sosial dan Pembangunan, vol. 17, no. 2, pp. 139–171.
 Abidin, H.Z., Andreas, H., Gumilar, I., et al. (2013). Land subsidence in coastal city of Semarang (Indonesia): characteristics, impacts and causes. Geomatics, Natural Hazards and Risk, vol. 4, no. 3, pp 226–240.
 Wirawan, A.R., Yuwono, B.D. and Sabri, L.M., (2019), Pengamatan penurunan muka tanah Kota Semarang metode survei GNSS tahun 2018. Jurnal Geodesi Undip, vol. 8, no. 1, pp. 418–427.
 Ferretti, A., Prati, C., and Rocca, F. (1999). Permanent scatterers in SAR interferometry, in IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS’99 Hamburg, Germany: IEEE.
 Hooper, A., Zebker, H., Segall, P. and Kampes, B., (2004). A new method for measuring deformation on volcanoes and other natural terrains using InSAR persistent scatterers, Geophysical research letters, vol 31, no 23, pp. 1-5.
 Azeriansyah, R., Prasetyo, Y., & Yuwono, B. D. (2019). Land Subsidence Monitoring in Semarang and Demak Coastal Areas 2016-2017 Using Persistent Scatterer Interferometric Synthetic Aperture Radar. IOP Conference Series: Earth and Environmental Science, vol. 313, no. 1, pp. 012–040.
 Prasetyo, Y., & Firdaus, H. S. (2019). Land Subsidence Of Semarang City Using Permanent Scatterer Interferometric Synthetic Aperture Radar (PS-Insar) Method In Sentinel 1a Between 2014-2017. In IOP Conference Series: Earth and Environmental Science vol. 313, no. 1, pp. 012-044.
 Azeriansyah, R., & Harintaka, H. (2019). Penggunaan Generic Atmospheric Correction Online Service For InSAR (GACOS) Pada Pemantauan Penurunan Muka Tanah di Kota Semarang Metode Persistent Scatterer Interferometric Synthetic Aperture Radar. ELLIPSOIDA, vol.2, no.01, pp. 101–106.
 Marker, B. R., and Bobrowsky, P. T. (ed.). (2013). Land Subsidence BT, in Encyclopedia of Natural Hazards, pp. 583–590. Dordrecht, Netherlands: Springer https://doi.org/10.1007/978-1-4020-4399-4_208
 Reddish, D.J. and Whittaker, B.N. (2012). Subsidence: occurrence, prediction and control, Amsterdam, Netherland: Elsevier.
 Chaussard, E. Amelung, F. & Abidin, H.Z. (2012). Sinking cities in Indonesia: Space-geodetic evidence of the rates and spatial distribution of land subsidence, In Proceedings of the FRINGE 2011 Workshop. pp. 19–23. Frascati, Italy: Proceedings of Fringe.
 Yuwono, B.D., Abidin, H.Z. & Hilmi, M. (2013). Analisa geospasial penyebab penurunan muka tanah di Kota Semarang, in Prosiding SNST ke-4, 1–12. Semarang: Fakultas Teknik Universitas Wahid Hasyim.
 Gumilar, I., Abidin, H.Z., Sidiq, T.P., et al. (2013). Mapping and evaluating the impact of land subsidence In Semarang (Indonesia), Indonesian Journal of Geospatial, vol. 2, no. 2, pp. 26–41.
 Bouraoui, S., (2013). Time series analysis of SAR images using persistent scatterer (PS), small baseline (SB) and merged approaches in regions with small surface deformation. France: Universitéde Strasbourg.  Parker, S.P. (1984). McGraw-Hill concise encyclopedia of science & technology, New York, USA: McGraw-Hill.
 Yu, Z., Li, Z. & Wang, S., (2015). An imaging compensation algorithm for correcting the impact of tropospheric delay on spaceborne high-resolution SAR, IEEE Transactions on Geoscience and Remote Sensing, 53, 9, 4825–4836.
 Wright, T., Fielding, E. & Parsons, B., (2001). Triggered slip: observations of the 17 August 1999 Izmit (Turkey) earthquake using RADAR interferometry, Geophysical Research Letters, 28, 6, 1079–1082.
 Hanssen, R.F., 2001, Radar interferometry: data interpretation and error analysis, Springer Science & Business Media.
 Bekaert, D.P.S., Walters, R.J., Wright, T.J., et al. (2015). Statistical comparison of InSAR tropospheric correction techniques. Remote Sensing of Environment, vol. 170, pp. 40–47. http://dx.doi.org/10.1016/j. rse.2015.08.035
 Gao, B., (2015). MODIS atmosphere L2 water vapor product. NASA MODIS adaptive processing system, Goddard Space Flight Center, USA.