Drought risk assessment during the dry season in Tien River estuary

With the development and widespread application of remote sensing technology and geographic information systems (GIS), the use of satellite images as well as GIS software is becoming more and more effective in monitoring, monitoring and assessing drought. In this study, the author assessed the risk of drought at Tien river estuary through two indices: Normalize Difference Vegetation Index (NDVI) and Standardized Precipitation Index (SPI) during the dry season months of 1991, 2001, 2010 and 2018.
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Drought risk assessment during the dry season in Tien River estuary DROUGHTRISKASSESSMENTDURINGTHEDRYSEASON INTIENRIVERESTUARY Abstract.Droughtsimplyisaperiodofmoisturedeficiency.Itdependsontemperature,evaporationcapacity, vegetationcover,topography,etc.,inaddition,itoftenhappensonalargescalemakingitdifficulttouse traditionalresearchmethods.Withthedevelopmentandwidespreadapplicationofremotesensingtechnology andgeographicinformationsystems(GIS),theuseofsatelliteimagesaswellasGISsoftwareisbecoming moreandmoreeffectiveinmonitoring,monitoringandassessingdrought.Inthisstudy,theauthorassessed theriskofdroughtatTienriverestuarythroughtwoindices:NormalizeDifferenceVegetationIndex(NDVI) andStandardizedPrecipitationIndex(SPI)duringthedryseasonmonthsof1991,2001,2010and2018.SPI values are interpolated to construct spatial modeling of meteorological drought levels. Through the LANDSATsatelliteimage,NDVIiscalculatedandbuiltonamapofdroughtlevels.WeightedoverlaySPI andNDVImaplayersforadroughtriskmap.ResearchresultshaveshownthattheTienriverestuaryareais dividedinto2zones:lightdroughtandmoderatedroughtoccursinthedryseason.Droughtoccurredwith strongintensityintheeasterncoastalareaofBenTreandTraVinhprovinces,thedeepertheinlandthelevel ofdroughtdecreased. Keywords:DroughtIndex,NDVI,SPI,Riskassessment,Tienriverestuary.1.Introduction Drought together with climate change is one of the prominent global issues so manyauthors in the world have studied drought research. But this is inherently severe naturalphenomenawithhighcomplexity,sofarthereisnogeneralmethodtostudytheproblemsofdrought.However,itisnowcommonintheworldforresearcherstousedroughtindicatorsintheirresearch.Amongthemeteorologicalindicators,since1996thegroupofauthorsMichaelJ.Hayes,Mark.D.Svobodaetal.[1]studieddroughtthroughtheStandardizedPrecipitationIndex(SPI).AndthenaseriesofotherauthorssuchasthestudyofdroughtclimateinEuropebyauthorBenjaminLloydHughesAndMarkA.Saunders[2](2002)alsoassesseddroughtbasedtheSPIandthePalmerdroughtseverityindex(PDSI);orresearchbyA.LoukasandL.Vasiliades[3](2004)assessingtheprobabilityofGreekdroughtthroughSPI. Through research, up to now, developed countries in the world have been aiming atmanaging drought. Therefore, the application of remote sensing technology in research,evaluationanddroughtmanagementhasbeenconcernedbymanyresearchersaroundtheworld.In2006,ParulChopra[4]researchedofdroughtriskassessmentbyremotesensingtechnologyandGISthroughNDVI,SPI,andfluctuationsinagriculturaloutputchainappliedtothespecificcaseistheGujaratarea,India.Ortheresearchofassessingtheriskofdroughtusingremote sensingandGIStechnology:ThecaseofthesouthernregionofTigray,EthiopiabyBirhanuGedifetal[5](2014)alsousedremotesensingtechnologyPredictingimage,calculatingNDVIandVegetationConditionIndex(VCI)toestablishandzoningdroughtriskmap.1 InVietnam,inrecentyears,therehavealsobeenmanyauthorsapplyingremotesensingtechnologyandGISindroughtresearch.In2013,theauthorLeThiThuHien[6]implementedtheprojectApplicationofplantindex(NDVI)ofLandsatimagetoassessthedesertificationofBinhThuanprovince.OrasthestudyApplicationofRemoteSensingtoAssessHanDroughtRiskinBacBinhDistrict,BinhThuanProvincebyTrinhLeHungandDaoKhanhHoai[7]presentedtheresultsofassessingtheriskofdroughtinthearea.BacBinhdistrict(BinhThuanprovince)from LANDSAT multispectral satellite image data using plant temperature drought index(TVDI). FortheMekongDeltaregioningeneralandtheTienRiverinparticular,therehavebeenmanystudiesondroughtinrecentyears.ExamplethereistheresearchBuildingmeteorologicalforecastingtechnologyintheMekongDeltabyNguyenDangTinhetal[8];orDevelopingdroughtmapoftheMekongDeltainthecontextofclimatechangebyauthorTranVanTyetal;theresearchDroughtfluctuationsinthedryseasoninTienGiangprovinceperiod19802015by Dao Ngoc Hung et al[9]. However, these research are mainly evaluated based onmeteorologicaldroughtindicators,butthereisnocomprehensiveevaluationofcriteriabelongingtodifferentdroughtgroups. Fromthesc ...