| Abstrakt: |
Drought has significant economic and social consequences, particularly in arid and semi-arid regions. The Mashhad Plain has recently experienced moderate to severe droughts, resulting in substantial damage to the agriculture and water sectors. This study aims to project changes in the characteristics of extreme droughts (SPI6 <-1) using outputs from the MRI-ESM2-0 model under two SSP scenarios. Additionally, the study investigated drought events through bivariate frequency analyses of drought duration and severity, based on SPI6 and the copula concept. Precipitation downscaling was performed using two methods: linear scaling (LS) and distribution mapping (DM). The LS method demonstrated superior downscaling capability based on statistical criteria. Projections for the near future (2026-2050) indicated an increase in precipitation under the SSP1-2.6 and SSP5-8.5 scenarios, with a statistically significant increase under SSP5-8.5. A decrease in drought frequency was observed under the SSP5-8.5 scenario based on SPI6-DM. Assessing future changes in characteristics of drought derived from the SPI6-LS series suggested an increase in drought frequency under the SSP5-8.5 scenario. Univariate return period analysis using the LS method indicated that, under the SSP1-2.6 scenario, drought events would remain unchanged compared to the baseline period. Conversely, under the SSP1-2.6 scenario (DM method), increased values of duration and severity were projected. Joint frequency analysis results suggested that under the SSP1-2.6 scenario, seasonal joint return periods of severity and duration would be shorter than the baseline, indicating an increased risk of drought hazards in the region under study. The application of these research results will contribute to improved future planning in the water and agriculture sectors for this area. [ABSTRACT FROM AUTHOR] |
