Prediction of the Climate Change and Radiative Forcing Scenarios on Monthly Runoff Urban Basin in Kerman, Iran.

Today, with any change in weather conditions, cities face various tensions. Air temperature is an essential indicator of climate change on Earth’s surface. With the slight increase in global heat, climate changes in the hydrological cycle accelerate. The most crucial feature is the effect on precipitation’s spatial and temporal distribution, leading to runoff volume changes. In this case, and considering urban development, addressing environmental issues becomes more important. This study predicts the Kerman basin’s monthly runoff under climate change conditions. It compares with the base period (1961–2005) of the CanESM2 general circulation model (GCM) under three Representative Concentration Pathway (RCP) scenarios: RCP2.6, RCP4.5, and RCP8.5 for the periods (2025–2050), (2051–2074), and (2075–2100). A decision support model named SDSM was used to downscale the data for this aim. Also, the Storm Water Management Model (SWMM) simulated the precipitation-runoff process. The results showed that the most significant changes were in the monthly precipitation pattern compared to the base period under the RCP2.6 scenarios (2075–2100), where the precipitation in September increased from 3 to 120 mm. However, under the RCP4.5 and RCP8.5 scenarios, it has decreased by 50 and 30 mm compared to the base period. Also, under the RCP2.6 and RCP8.5 scenarios (2051–2074), the precipitation increased by 8.5 mm and 6 mm in February and January, respectively. Consequently, the runoff, considering infiltration and evaporation, has increased by 7.55 mm under the RCP2.6 scenario and 5.65 mm under the RCP8.5 scenario. [ABSTRACT FROM AUTHOR]