Evaluating the impact of climate change on temperature and precipitation using the LARS-WG model (Case study of Bashar River watershed)

The increase of greenhouse gases and the resulting increase in temperature have caused the balance of the earth's climate system and climate changes in most areas of the earth. Therefore, adapting and dealing with climate changes in the water resources sector along with reducing their reflection should be seriously addressed as part of a comprehensive regional response to the vulnerability caused by climate change. In this study, using LARS-WG exponential microscale software and the HadCM3 oceanic atmospheric general circulation model in the form of different scenarios defined in the fourth IPCC report (basic scenarios), including scenarios A1, A2, B1, and B2, which are more related to regional issues. And the world is concerned from an economic and environmental point of view, the amount of temperature changes and precipitation in the next 100 years of the Bashar river basin was predicted. Then the fifth report scenario (RCP) was used and the results were compared with the basic scenarios. The results showed that in both scenarios in the coming period, we will face a large increase in average air temperature, but the decrease in precipitation will not be significant. In the climate change scenario section, RCPs until the end of the 21st century indicate an increase in temperature and a decrease in precipitation in the coming years. The amount of temperature changes in RCP2.6 was estimated between 3 and 13% and in RCP8.5 between 4 and 14%, which increase in temperature on a large scale increases evaporation and prolongs drought periods