Drought Spatial Analysis using remote sensing technique(Case study: Maharlo Bakhtegan Basin)

Drought is one of the most destructive climatic phenomena whose impact is more significant at the regional scale. The importance of drought in an area such as Maharloo Bakhtegan is more important due to the strategic conditions of the region, the extent of agricultural lands and the existence of Maharloo and Bakhtegan lakes. The purpose of this study was to assess drought using remote sensing, spatial statistics, and GIS in the Maharloo-Bakhtegan basin. In this study, to evaluate the effect of drought on vegetation, Madis images were used to calculate the normalized vegetation index (NDVI) and then the changes in vegetation area were investigated. The results showed that the area of vegetation decreased in the studied years. Reasons for these changes can be attributed to reduced winter rainfall, land-use changes, increased off-season grazing, and bushes. The results indicate the drought in the region. Also to study drought in Maharloo-Bakhtegan basin, meteorological data for estimation of normalized precipitation index (SPI) and spatial statistical analysis, from 6 selected synoptic stations (Shiraz, Zarghan, Droodzan Dam, Eqlid, Neyriz, and Abadeh) used from 1999 to 2018. The results of the Moran index for drought showed that the values for different years have a positive coefficient and close to one during the statistical period, indicating that the SPI drought index data have a cluster pattern. The results of the Z standard score and P-value also confirmed the clustering of the spatial distribution of drought.