Investigation of spatiotemporal changes of meteorological drought with discrepancy precipitation index in Seyhan, Ceyhan, Eastern Mediterranean and Asi Basin regions

The increase in temperature values and rapid escalation of the population leads to severe drought periods, the effects of which our country is already sensitive for. For this reason, it is crucial to determine dry and wet periods practically and provide information for regional management plans. In this context, dry and wet period analyses were carried out using meteorological drought indices in the Seyhan, Ceyhan, Asi River and Eastern Mediterranean basins, which are under the influence of our country's arid and semi-arid climate zone. Standardized Precipitation Index (SPI) and Discrepancy Precipitation Index (DPI) values were obtained with 52 years (1970-2021) of precipitation data obtained from the Turkish State Meteorological Service (MGM) for 21 stations. Spatiotemporal changes in the results were evaluated with various graphs. By determining the number of occurrences, frequency and severity of wet and dry periods, the transition probabilities between drought classifications were examined. As a result, it was determined that the driest year occurred in Göksun in 2013, and the wettest year occurred in 2009 in the Karataş region. While humid periods can be detected more precisely with SPI-Gamma values, dry periods can be detected more specifically with the SPI-Lognormal method. Dry periods occur much more frequently in the DPI method compared to the SPI method. According to the results of all indices, the years 1980, 1990, 2007, 2014, and 2016 were dry; the years 1981, 2001 and 2009 were determined to be wet. Based on the SPI results, it is thought that as the level of drought categories decreases, while their frequency increases.