نوع مقاله : پژوهشی
نویسندگان
1 گروه منابع طبیعی و محیط زیست، واحد علوم و تحقیقات، دانشگاه ازاد اسلامی، تهران، ایران
2 گروه منابع طبیعی و محیط زیست، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران
3 دانشکده احیای مناطق خشک و کوهستانی، دانشگاه تهران، کرج، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction and Goal
Climate change refers to long-term, irreversible changes in average climate conditions caused by natural and human factors, leading to global temperature increases, melting of polar ice caps, rising sea levels, and extreme weather events. These changes have a significant impact on meteorological variables such as temperature and precipitation, which disrupt hydrological order. General circulation models are advanced and comprehensive tools used to simulate and predict these changes based on atmospheric dynamic and thermodynamic processes. Therefore, climate change projections under the Sixth Report models have been carried out in the Bakhtegan-Maharloo watershed.
Materials amd Methods
In this study, daily precipitation and minimum and maximum temperature data from five synoptic stations of Arsanjan, Neyriz, Safashar, Shiraz and Takht Jamshid were used. Climatic parameters were downscaled using the models of the Sixth Report of the Intergovernmental Panel on Climate Change using the LARS-WG model. The station type was selected based on data adequacy, dispersion and climatic diversity in the watershed. In this study, the output of three models ACCESS-ESM1-5, CNRM-CM6-1 and MRI-ESM2-0 was used using three scenarios SSP126, SSP245 and SSP585.
Using the LARS-WG8 statistical model, exponential downscaling and correction of precipitation and minimum and maximum temperature data were performed to increase the accuracy of the predictions. Finally, the climate forecast for the period 2026 to 2045 was calculated and processed by processing the daily precipitation and temperature data of the synoptic stations of the Bakhtegan-Maharloo watershed and comparing them with the base period.
Results and Discussion
The results showed that the ACCESS-ESM1-5 model had a significant difference between the average precipitation of the base period and the future at the 95% confidence level and predicted higher precipitation than the other two models, and the CNRM-CM6-1 and MRI-ESM2-0 models were closer to the base period values. The predicted maximum temperature at all stations and scenarios increased compared to the observational data and was estimated to be significant and upward at the 95% confidence level. The average annual maximum temperature increased from 24.8°C to 26.9°C. The CNRM-CM6-1 model predicted the highest maximum temperature. Shiraz and Persepolis have the highest temperatures. The minimum temperature at all stations has an increasing trend and the average watershed temperature has increased from 9.7°C to 11.5°C (in the SSP585 scenario). This indicates warmer nights and a decrease in nighttime cold. The CNRM-CM6-1 model usually predicts higher minimum temperatures than other models. The range of predicted precipitation changes in the area is estimated from 248.9 to 288.7 mm, and the range of maximum and minimum temperature changes is estimated from 26 to 26.9 and 11 to 11.9 °C, respectively.
Results and Discussion
The results showed that the ACCESS-ESM1-5 model had a significant difference between the average precipitation of the base period and the future at the 95% confidence level and predicted higher precipitation than the other two models, and the CNRM-CM6-1 and MRI-ESM2-0 models were closer to the base period values. The predicted maximum temperature at all stations and scenarios increased compared to the observational data and was estimated to be significant and upward at the 95% confidence level. The average annual maximum temperature increased from 24.8°C to 26.9°C. The CNRM-CM6-1 model predicted the highest maximum temperature. Shiraz and Persepolis have the highest temperatures. The minimum temperature at all stations has an increasing trend and the average watershed temperature has increased from 9.7°C to 11.5°C (in the SSP585 scenario). This indicates warmer nights and a decrease in nighttime cold. The CNRM-CM6-1 model usually predicts higher minimum temperatures than other models. The range of predicted precipitation changes in the area is estimated from 248.9 to 288.7 mm, and the range of maximum and minimum temperature changes is estimated from 26 to 26.9 and 11 to 11.9 °C, respectively.
Conclusion and Suggestion
The overall trend of increasing precipitation and temperature (maximum and minimum) is consistent with the severity of greenhouse gas emission scenarios and indicates a warmer and relatively wetter Bakhtegan-Maharlu region in the future. The differences between models indicate uncertainty in projections, which necessitates the use of multiple models and scenarios to reduce decision-making risk. These changes require careful planning and adaptation for water resource management, agriculture, and public health in the region.
کلیدواژهها [English]
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