Abstract:
Increasing quantitative and qualitative awareness of the magnitude of climate parameter changes in the future and assessing their subsequent impacts is the primary motivation in climate change studies. Predicting and estimating climate parameters, including maximum temperature, is considered one of the most critical indicators of climate change at global and regional scales. This study aims to evaluate and predict the trends of maximum temperature changes in Hamedan city for the period 2021–2100. To achieve this objective, the CanESM2 General Circulation Model and the Statistical Down Scaling Model (SDSM) were utilized. Following the validation of the SDSM model using observational data and NCEP reanalysis data, the maximum temperature was predicted based on different Representative Concentration Pathway scenarios (RCP2/6, RCP4/5, and RCP8/5). The results indicate that the maximum temperature in Hamedan city will experience an increasing trend in the long-term horizon (2021–2100) under the influence of climate change. The highest monthly growth rate of maximum temperature was estimated for the optimistic RCP2/6 scenario in April, with an increase of 1/2 °C, indicating the occurrence of early spring warming and the high sensitivity of the region even under greenhouse gas emission control. Furthermore, under the intermediate (RCP4/5) and pessimistic (RCP8/5) scenarios, January, February, and April exhibited the highest increases. On a seasonal scale, only under the pessimistic RCP8/5 scenario will the maximum temperature significantly increase during the spring, summer, and autumn seasons. However, the behavior of the region's climate system is not entirely uniform, and limited decreasing fluctuations are also observed in certain months and scenarios (particularly under the RCP2/6 scenario in January) compared to the base period. Overall, the results demonstrate the dominance of the increasing trend in the maximum temperature of Hamedan city during future periods (2100-2021) under the influence of various climate scenarios, highlighting the necessity of addressing the impacts of warming for the future management and planning of this city.