The effect of drought on pasture changes using remote sensing technique (case study of Haji Abad city, Hormozgan province)

Drought, as one of the most destructive natural disasters, has extensive negative effects on the environment and human life. Meteorological data is used in this research. Among these data, SPI standardized precipitation index and ZSI score index (Z) are used. The bands used by MODIS gauge include bands 1 to 7, 31 and 32. In order to calculate the drought indices, SPI-SL-6 and DIP software, which are designed based on the monthly time scale, were used for a 3-month time series. To prepare the layer in the ERDAS IMAGINE program, the stack layer is prepared and in the ArcGIS program, the border of Haji Abad city is separated and finally the NDVI and LST layers related to each year are extracted. The investigation of the occurrence of meteorological drought by the SPI _3 index in the stations located in the study area indicates that the region had normal years in terms of drought during the years 1391 to 1393, which intensified in the years 1994 to 1995. But during the years 1996 to 1400, we witness the occurrence of droughts with different degrees in the region, which intensified during the years 1998 to 1400. The investigation of meteorological drought using the ZSI index in the period of 2011 to 2014 and in 3-month intervals in the studied area shows almost the same results as the SPI index. . The comparison of SPI and ZSI values in different years shows a very high correlation in the first 3 months of each year, considering that a significant decrease in vegetation and pastures has occurred in each period of time, which has caused the impoverishment of pastures. At a glance, it is important to note that the most drought-affected areas are low-density pastures.