Penerapan Koreksi Troposfer pada Metode PS-InSAR untuk Pemantauan Penurunan Permukaan Tanah di Kota Surabaya

Ulma, Toifatul (2021) Penerapan Koreksi Troposfer pada Metode PS-InSAR untuk Pemantauan Penurunan Permukaan Tanah di Kota Surabaya. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Permanent Scatterer Interferometry Synthetic Aperture Radar (PS-InSAR) merupakan salah satu metode dari teknologi radar yang dapat digunakan untuk pemetaan estimasi penurunan permukaan tanah. Metode ini memiliki kemampuan mengamati area yang cukup luas dalam waktu singkat. Hal ini juga terkait dengan tipikal iklim di Indonesia yang terletak di area tropis (intensitas dan sebaran tutupan awan yang tinggi). Namun, kemampuan citra Synthetic Aperture Radar (SAR) yang mampu menembus awan dan digunakan di berbagai kondisi, tidak akan terlepas dari kesalahan troposfer. Permasalahan ini disebut dengan tropospheric delay pada masing-masing citra yang berdampak pada hasil akurasi PS-InSAR. Generic Atmospheric Correction Online Service (GACOS) merupakan data eksternal bersifat real time dan mempunyai cakupan global yang dapat digunakan untuk koreksi troposfer dari PS-InSAR. Dalam penelitian ini, data GACOS digunakan untuk mengoreksi kesalahan troposfer pada pengolahan PS-InSAR. Kota Surabaya sebagai kota padat penduduk dipilih sebagai daerah penelitian. Sebanyak 81 citra Sentinel-1A digunakan untuk mendeteksi penurunan muka tanah di Kota Surabaya dimulai dari Maret 2017 hingga Desember 2019. Pengaruh GACOS pada PS-InSAR dianalisa dengan membandingkan hasil dari PS-InSAR non-GACOS dan divalidasi dengan data penurunan permukaan tanah dari GPS. Hasil dari penelitian ini menunjukkan bahwa, akurasi pemantauan penurunan permukaan tanah meningkat di seluruh area studi setelah dilakukan koreksi troposfer dengan data GACOS. Selisih rata-rata antara PS-InSAR sebelum dan sesudah koreksi troposfer adalah sebesar 1,734 mm/tahun dengan standar deviasi ±0,550 mm/tahun. Uji signifikansi dua variabel 95% menunjukkan koreksi troposfer dengan data GACOS mampu mempengaruhi hasil PS-InSAR. Namun, koreksi troposfer dengan data GACOS dapat meningkatkan kesalahan di beberapa titik. Hal ini dimungkinkan terjadi karena terkait dengan rendahnya akurasi data turbulensi dari GACOS. ====================================================================================================== Permanent Scatterer Interferometry Synthetic Aperture Radar (PS-InSAR) is a method of radar technology that can be used for mapping the estimation of land subsidence. This method could observe the widely area in a short time and is related to the typical climate in Indonesia which is located in the tropics (high intensity and distribution of cloud cover). However, the ability of SAR imagery that is able to penetrate clouds and be used in various conditions will not be separated from tropospheric effect. This problem is called tropospheric delay in each image which has an impact on the accuracy of PS-InSAR. General Atmospheric Correction Online Service (GACOS) is an external data that is real time and has global scope that can be used for atmospheric correction from PS-InSAR. In this study, GACOS data were used to correct for atmospheric errors in PS-InSAR processing. The city of Surabaya as a densely populated city was chosen as the research area. 81 Sentinel-1A images were used to detect land subsidence in the city of Surabaya starting from March 2017 to December 2019. The effect of GACOS on PS-InSAR was analyzed by comparing the results from non-GACOS PS-InSAR and validated with land subsidence data from GPS. The results of this study indicate that the accuracy of monitoring land subsidence increases throughout the study area after tropospheric correction using GACOS data. The average difference between PS-InSAR before and after tropospheric correction is 1.734 mm/year with a standard deviation of +0.550 mm/year. The significance test of two variables 95% showed that the tropospheric correction with GACOS data was able to affect the PS-InSAR results. However, tropospheric correction with GACOS data can increase the error at some point. This is possible because it is related to the low accuracy of the turbulence data from GACOS.

Item Type: Thesis (Masters)
Uncontrolled Keywords: GACOS, Koreksi Troposfer, Penurunan Muka Tanah, PS-InSAR, GACOS, Tropospheric Correction, Land Subsidence
Subjects: G Geography. Anthropology. Recreation > G Geography (General) > G109.5 Global Positioning System
G Geography. Anthropology. Recreation > G Geography (General) > G70.5.I4 Remote sensing
H Social Sciences > HV Social pathology. Social and public welfare > HV551.5.I4 Hazard mitigation
T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TA Engineering (General). Civil engineering (General) > TA590 Topographical surveying
T Technology > TD Environmental technology. Sanitary engineering > TD194.6 Environmental impact analysis
T Technology > TD Environmental technology. Sanitary engineering > TD890 Global Environmental Monitoring System
Divisions: Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29101-(S2) Master Thesis
Depositing User: Toifatul Ulma
Date Deposited: 18 Aug 2021 14:06
Last Modified: 18 Aug 2021 14:06
URI: https://repository.its.ac.id/id/eprint/87667

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