Spatiotemporal analysis of transition probabilities of wet and dry days under SSPs scenarios in the semi-arid Susurluk Basin, Türkiye

• Published in: The Science of the total environment Vol. 912; p. 168641
• Main Authors: Şan, Murat, Nacar, Sinan, Kankal, Murat, Bayram, Adem
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.02.2024
• Subjects: Climate change; CMIP6 archive; SSPs scenarios; Statistical downscaling; Transition probabilities; Wet and dry days; Transition probabilities; Climate change; Wet and dry days; Statistical downscaling; SSPs scenarios; CMIP6 archive
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.168641

Precipitation, especially in regions dominated by the Mediterranean climate, is one of the most critical parameters of the hydrological cycle and the environment affected by climate change. One the one hand, the transition probabilities of wet and dry days in precipitation occurrence are a relatively new topic, on the other hand these are essential in defining the regional climate. For the first time, spatiotemporal variations of transition probabilities of wet and dry days in the Susurluk Basin, northwestern Türkiye, dominated by a semi-arid Mediterranean climate and also having a mountain climate, were analyzed based on the observation (1979–2014) and future terms (2030–2059 as short and 2070–2099 as long), under four Shared Socioeconomic Pathways (SSPs) scenarios. To do this, statistical downscaling was performed for 14 general circulation models (GCMs) from the CMIP6. By applying an ensemble of four high-performing GCMs, four indices for transition probabilities of wet and dry, i.e., a dry day following a dry day (FDD), a wet day following a dry day (FDW), a dry day following a wet day (FWD), and a wet day following a wet day (FWW), were calculated, and their changes were determined statistically. Monotonic and partial trends of the indices were also analyzed. According to the results, the FDD will increase in water year and wet period and autumn in the future, especially for the long term, in the basin dominated by the FDD (75 % in water year). The risks are higher in the western part of the basin, where human activities are intense, as the FDD is higher in this part than other parts especially in summer (90–100 %) in SSP3-7.0 and SSP5-8.5 scenarios for the long term. So, the length of consecutive dry days in the wet period and water year will increase in the basin, thus increasing the likelihood of droughts. As for the intra-term trends, the FDD increases and the FWW decreases in the water year and seasons in SSP3-7.0 and SSP5-8.5, contrary to the observation term. [Display omitted] •Statistical downscaling of daily precipitation was performed with 14 GCMs under SSP scenarios.•Spatiotemporal analysis of transition probabilities of wet and dry days was examined•Probabilities of FDD, which is already high, will increase even more in the far future than in the near future.•Contrary observation, increase of FDDs and decrease of FWWs will be especially for SSP3-7.0 and SSP5-8.5.•Dry areas will tend to dry out more.