Drought analysis of Southeastern Anatolia Region by standardized precipitation index (SPI)

In this study, droughts in the nine provinces (Şırnak, Mardin, Batman, Diyarbakır, Gaziantep, Siirt, Şanlıurfa, Kilis and Adıyaman) of the Southeastern Anatolia Region was analyzed by the use of Standardized Precipitation Index (SPI) that was developed for the determination and monitoring of meteorological droughts. In the drought analysis, monthly total rainfall data from the meteorological stations in each province covering 1970-2017 period were used. SPI time series were calculated for 3, 6, 12 and 24 month scales. Mann-Kendall trend test was applied to the calculated SPI values in order to determine whether there is an increasing or decreasing trend of drought in the region. In addition, the distribution of drought in the region was mapped with the use of ArcGIS-ArcMap program for periods in which extreme SPI values observed. As a result of the study, it was determined that the SPIs of 3, 6, 12 and 24 months reached to the extreme values in 1973, 1988, 1989, 2008 and 2009 in Southeastern Anatolia Region. In Mardin, Kilis and Şanlıurfa provinces, there is a decreasing trend for long-term (12-24 months) SPI series, in other words, there is a tendency to increase in severe and extreme droughts. It has been concluded that droughts tend to decrease in Şırnak and Gaziantep provinces.