Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent

Malaysia is affected by floods almost every year. In this situation, high-frequency flood monitoring is crucial so that timely measures can be taken. However, the low revisit time of the satellites, as well as occlusion cast by clouds in optical images, limits the frequency of flood observation of t...

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Autores principales:	Husniyah Binti Mahmud, Vaibhav Katiyar, Masahiko Nagai
Formato:	article
Lenguaje:	EN
Publicado:	Hindawi Limited 2021
Materias:	Engineering (General). Civil engineering (General) TA1-2040 Mathematics QA1-939
Acceso en línea:	https://doaj.org/article/f27919fe5639479daf7c46e02b51494e
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spelling	oai:doaj.org-article:f27919fe5639479daf7c46e02b51494e2021-11-15T01:19:12ZImproved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent1563-514710.1155/2021/6164161https://doaj.org/article/f27919fe5639479daf7c46e02b51494e2021-01-01T00:00:00Zhttp://dx.doi.org/10.1155/2021/6164161https://doaj.org/toc/1563-5147Malaysia is affected by floods almost every year. In this situation, high-frequency flood monitoring is crucial so that timely measures can be taken. However, the low revisit time of the satellites, as well as occlusion cast by clouds in optical images, limits the frequency of flood observation of the focused area. Therefore, this study proposes utilising multisatellite data from optical satellites such as Landsat 7, Landsat 8, and Moderate Resolution Imaging Spectroradiometer (MODIS), as well as Synthetic Aperture Radar (SAR) images from Advanced Land Observation Satellite (ALOS-2) and Sentinel-1, to increase observation of flood. The main objective was to utilize Otsu image segmentation over both optical and SAR satellite images to distinguish water and nonwater areas in each image separately. For this, modified normalized difference water index (MNDWI) for the optical satellite and total dual-polarization backscatter for SAR satellite images were estimated. The focused area has been divided into Universal Transverse Mercator (UTM) square-size grids of 30 pixels, and each satellite image was reprojected and resampled with a pixel size of 0.001° to standardize the flood map resolution. The second objective was to assess the potential of image fusion for increasing the consistency of water area extraction. Two pairs of satellite images with the same observation period covering a flood event in September 2017 in Perlis, Malaysia, were processed using 2D wavelet transform. Lastly, the temporal changes of the integrated surface water extent were evaluated by comparing the output from both multisatellite and fused images with the observed water level data from the Department of Drainage and Irrigation. The results showed that the proposed model can be used to estimate flood duration as well as to estimate the flood-related losses, especially in ungauged or data-poor regions.Husniyah Binti MahmudVaibhav KatiyarMasahiko NagaiHindawi LimitedarticleEngineering (General). Civil engineering (General)TA1-2040MathematicsQA1-939ENMathematical Problems in Engineering, Vol 2021 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Engineering (General). Civil engineering (General) TA1-2040 Mathematics QA1-939
spellingShingle	Engineering (General). Civil engineering (General) TA1-2040 Mathematics QA1-939 Husniyah Binti Mahmud Vaibhav Katiyar Masahiko Nagai Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent
description	Malaysia is affected by floods almost every year. In this situation, high-frequency flood monitoring is crucial so that timely measures can be taken. However, the low revisit time of the satellites, as well as occlusion cast by clouds in optical images, limits the frequency of flood observation of the focused area. Therefore, this study proposes utilising multisatellite data from optical satellites such as Landsat 7, Landsat 8, and Moderate Resolution Imaging Spectroradiometer (MODIS), as well as Synthetic Aperture Radar (SAR) images from Advanced Land Observation Satellite (ALOS-2) and Sentinel-1, to increase observation of flood. The main objective was to utilize Otsu image segmentation over both optical and SAR satellite images to distinguish water and nonwater areas in each image separately. For this, modified normalized difference water index (MNDWI) for the optical satellite and total dual-polarization backscatter for SAR satellite images were estimated. The focused area has been divided into Universal Transverse Mercator (UTM) square-size grids of 30 pixels, and each satellite image was reprojected and resampled with a pixel size of 0.001° to standardize the flood map resolution. The second objective was to assess the potential of image fusion for increasing the consistency of water area extraction. Two pairs of satellite images with the same observation period covering a flood event in September 2017 in Perlis, Malaysia, were processed using 2D wavelet transform. Lastly, the temporal changes of the integrated surface water extent were evaluated by comparing the output from both multisatellite and fused images with the observed water level data from the Department of Drainage and Irrigation. The results showed that the proposed model can be used to estimate flood duration as well as to estimate the flood-related losses, especially in ungauged or data-poor regions.
format	article
author	Husniyah Binti Mahmud Vaibhav Katiyar Masahiko Nagai
author_facet	Husniyah Binti Mahmud Vaibhav Katiyar Masahiko Nagai
author_sort	Husniyah Binti Mahmud
title	Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent
title_short	Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent
title_full	Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent
title_fullStr	Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent
title_full_unstemmed	Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent
title_sort	improved consistency of an automated multisatellite method for extracting temporal changes in flood extent
publisher	Hindawi Limited
publishDate	2021
url	https://doaj.org/article/f27919fe5639479daf7c46e02b51494e
work_keys_str_mv	AT husniyahbintimahmud improvedconsistencyofanautomatedmultisatellitemethodforextractingtemporalchangesinfloodextent AT vaibhavkatiyar improvedconsistencyofanautomatedmultisatellitemethodforextractingtemporalchangesinfloodextent AT masahikonagai improvedconsistencyofanautomatedmultisatellitemethodforextractingtemporalchangesinfloodextent
_version_	1718429019785920512

Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent

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