Impact of Climate Change on Precipitation and Temperature by Taking the Uncertainty of Models and Climate Scenarios (Case Study: Shahrchay Basin in Urmia)

Temperature and precipitation are two important parameters in hydrology and water resources. The impact of climate change on these two parameters has been the subject of many studies and studying atmospheric general circulation models is one of the best methods to estimate its effects. In the studies of climate change, lack of uncertainty in various stages of evaluation for the effect of climate change reduce certainty and confidence of the final outputs. In this study for analyzing the effects of climate change on precipitation and temperature in Shahrchay basin and the effects of the uncertainty related to general circulation models, six atmospheric general circulation model and 3 scenarios, A1B, A2 and B1 were downscaled by using LARS-WG. For evaluating the uncertainty of the models and scenarios, the output of models in the future and based period were compared by monthly statistical indices, coefficient of determination (R2) and Root Mean Square Error (RMSE) and the best models and scenarios for producing temperature and precipitation data were selected for the period 2011-2030. As the results, the HADCM3 model under scenarios A1B was used for precipitation and the MPEH5 under scenarios A2 for temperature production. The results of this research showed that in the future period rainfall will be reduced about 9 millimeter, while the minimum and maximum temperature will increase 1.05 and 0.87 °C respectively. Disruptions of rainfall distribution and high temperature have significantly negative consequences than rainfall reduction.