Drought assessment in the northeastern Aras Basin using multi-parameter aggregate drought index and innovative polygon trend analysis

Drought is a climate phenomenon that can have serious consequences for all living things. The widespread occurrence of extreme drought and extreme precipitation conditions in recent years has increased the importance of drought studies. This study aims to conduct a comprehensive drought analysis using 11 meteorological parameters for the period 1970-2023 at Ardahan, I & gbreve;d & imath;r, and Kars meteorological stations in the region of T & uuml;rkiye, which is located in the Northeast of the Aras Basin and known for its harsh winter conditions. Drought analysis was carried out with the Aggregate Drought Index (ADI) method and the effects of climate change on parameters such as temperature, precipitation, snow water equivalent (SWE), and streamflow in the region were analyzed. As a result of the study, with the use of ADI and IPTA methods, drought trends in Aras Basin, especially in the winter and summer seasons, were clearly seen. It can be said that near-normal conditions are experienced the most with a frequency of approximately 20%. In addition to the ADI analysis, Standardized Precipitation Index (SPI), Streamflow Drought Index (SDI), and Reconnaissance Drought Index (RDI) methods were also applied; however, it was observed that these indexes do not always show full agreement with the ADI and exhibit similar trends in some drought periods. These results show that choosing the right indexes is of great importance for drought analysis and that indexes suitable for regional climate characteristics will give more reliable results.