Drought trend analysis in a semi-arid area of Iraq based on Normalized Difference Vegetation Index, Normalized Difference Water Index and Standardized Precipitation Index

作     者：Ayad M F AL-QURAISHI Heman A GAZNAYEE Mattia CRESPI Ayad M F AL-QURAISHI;Heman A GAZNAYEE;Mattia CRESPI

作者机构：Department of Surveying and Geomatics EngineeringFaculty of EngineeringTishk International UniversityErbil 44001Iraq Department of ForestryCollege of Agricultural Engineering SciencesSalahaddin UniversityErbil 44002Iraq Geodesy and Geomatics DivisionDepartment of CivilConstructional and Environmental EngineeringSapienza University of RomeRome 00185Italy Sapienza School for Advanced StudiesSapienza University of RomeRome 00185Italy 

出 版 物：《Journal of Arid Land》 (干旱区科学（英文版）)

年 卷 期：2021年第13卷第4期

页      面：413-430页

核心收录：

学科分类：0710[理学-生物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 0815[工学-水利工程] 0705[理学-地理学] 0706[理学-大气科学] 0713[理学-生态学] 

基　　金：College of Agricultural Engineering Sciences Salahaddin University U.S. Geological Survey, USGS 

主　　题：climate change drought Normalized Difference Vegetation Index(NDVI) Normalized Difference Water Index(NDWI) Standardized Precipitation Index(SPI) delay effect 

摘      要：Drought was a severe recurring phenomenon in Iraq over the past two decades due to climate change despite the fact that Iraq has been one of the most water-rich countries in the Middle East in the past.The Iraqi Kurdistan Region(IKR)is located in the north of Iraq,which has also suffered from extreme drought.In this study,the drought severity status in Sulaimaniyah Province,one of four provinces of the IKR,was investigated for the years from 1998 to 2017.Thus,Landsat time series dataset,including 40 images,were downloaded and used in this study.The Normalized Difference Vegetation Index(NDVI)and the Normalized Difference Water Index(NDWI)were utilized as spectral-based drought indices and the Standardized Precipitation Index(SPI)was employed as a meteorological-based drought index,to assess the drought severity and analyse the changes of vegetative cover and water bodies.The study area experienced precipitation deficiency and severe drought in 1999,2000,2008,2009,and 2012.Study findings also revealed a drop in the vegetative cover by 33.3%in the year 2000.Furthermore,the most significant shrinkage in water bodies was observed in the Lake Darbandikhan(LDK),which lost 40.5%of its total surface area in 2009.The statistical analyses revealed that precipitation was significantly positively correlated with the SPI and the surface area of the LDK(correlation coefficients of 0.92 and 0.72,respectively).The relationship between SPI and NDVI-based vegetation cover was positive but not significant.Low precipitation did not always correspond to vegetative drought;the delay of the effect of precipitation on NDVI was one year.