Document Type : Research
Authors
1
PhD Graduated in Watershed Management, Faculty of Natural Resources, Urmia University, Urmia, Iran
2
Assistant professor, Department of Range and Watershed Management, Faculty of Natural Resources, Malayer University, Malayer, Iran
3
3Associate Professor, Department of Range and Watershed Management, Faculty of Natural Resources, Hormozgan University, Bandarabbas, Iran
4
M.sc. Graduated in Watershed Management, Department of Range and Watershed Management, Faculty of Natural Resources, Malayer University, Malayer, Iran
10.22092/wmrj.2024.364521.1565
Abstract
The simulation results for precipitation in the period 2030-2050 show that the synoptic stations will experience uneven annual fluctuations . At some stations, precipitation will increase compared to the base period (1987-2022), while at others it will decrease. The highest increase in precipitation was observed at Bam station under the SSP5-8.5 scenario with a magnitude of 81.59% (32.32 mm), and the highest decrease in annual precipitation was observed at Kish station under the SSP5-8.5 scenario with a magnitude of 63.11% (23.17 mm). The results indicate that most indices of precipitation extremes at the investigated stations show a decreasing trend in the period 1985-2022. For the PRCPTOT index, about 50% of these changes were significant; significant increasing and decreasing trends accounted for 25.53% and 27.66% of all trends, respectively. For the other indices, less than 30% of the trends were significant. These results are consistent with those of Jahanbakhsh Asl et al (2015), Koozehgaran and Mousavi Baigi (2015), Hajizadeh et al (2023), Alavinia et al (2022), Jokar et al (2021), Zand et al (2023), Eskandari et al (2024) and Fathiyan et al (2020). According to the results of the spatial distribution of the annual precipitation sum (PRCPTOT), the highest increase in annual precipitation was observed at the Yasouj station under the SSP1-2.6 scenario. On the other hand, under the SSP5-8.5 scenario, the Tabriz station was projected to have the largest decrease in annual precipitation at 165.11 mm (68%). Geographically, the stations in the Zagros Mountains region showed a more pronounced downward trend than other parts of the country. This suggests that the decline in annual precipitation in the northern and north-western regions of Iran is more pronounced than in the central and southern parts. These results are consistent with the studies of Mohammadi et al. (2017) and Askarizadeh et al. (2018), while Koozehgaran et al. (2015), Alavinia et al. (2020), Kazemirad and Madbari (2023) and Hajizadeh et al. (2023) reported a decrease in the PRCPTOT index under different scenarios in their studies conducted in Torbat Heydariyeh, Birjand, Tabas, Qazvin and Kurdistan. The analysis of changes in precipitation extreme indices in the period 2030-2050 compared to 1985-2022 showed that the most significant changes are observed in the northern and western regions of Iran, with the intensity of these changes being higher, especially under the SSP5-8.5 scenario. The strongest decrease in the Rx1day index was observed at the Mashhad station under the SSP5-5.5 scenario with a magnitude of 37%. The strongest increase was observed at the Zanjan station under the RCP8.5 scenario. In addition, the strongest decrease in annual precipitation of 165.11 mm (68%) was forecast for the Tabriz station under the SSP5-8.5 scenario.
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