A new framework to spatial and temporal drought analysis for 1990-2020 period with Mann-Kendall and innovative trend analysis methods in Turkey

With the escalating global impacts of climate change, the prevalence of drought has become a pressing concern. Effective routine observation and analysis of drought have gained paramount importance. Future drought policies are adversely affected due to the inability to accurately reflect the drought changes caused by spatial differences in analysis studies. A new approach is required. Presenting a novel perspective, this study focuses on a comprehensive temporal and spatial analysis of drought occurrences in Turkey. Employing the 12-month standardized precipitation index (SPI) calculated from data spanning 1990 to 2020, the study undertook rigorous geographic information system (GIS)-based spatial processing. After the areal sizes were calculated, drought trends were revealed by applying both Mann-Kendall (MK) and innovative trend analysis (ITA) tests on percentile areas. The assessment encompassed five distinct categories, with individual trend analyses conducted for each category. Significance levels of 1%, 5%, and 10% were applied in both trend tests. The evaluation of province-level and regional-level drought trends was conducted following the generation of province-based areal trend maps. The findings revealed a declining trend within the humid categories along the Black Sea and Mediterranean coastal regions, and the inland provinces of Eastern Anatolia. Additionally, an areal change was detected from relatively more humid or drier classes to near normal classes. This study's outcomes enhance long-term drought assessment and monitoring at national and regional scales. This new approach in drought analysis, determined according to Turkey's conditions, can be used in future drought planning by eliminating spatial differences in the international sense.