Investigating the Use of Weather Generator Models Simulation Instead of the Output of Climate Change Models in Predicting Design Precipitation(Case study: Tehran, Mehrabad Station)

Due to global warming and the occurrence of climate change and its effect on meteorological variables, especially rainfall, which is a key parameter in urban infrastructure design and water resources management, studies in this area are very important. It is now possible to predict future rainfall using the output of climate change models; this is however accompanied by many problems including lack of easy access, being large scale and the need for spatial and temporal micro scaling, increasing error, and imposing risk to urban flood management structures. Therefore, the application of a weather generator model with the ability of climatic models in simulating future precipitation using observational and recorded data has been considered in this research. In the present study, the non-parametric K-NN WG model was used which produces data outside the observational range by using two mechanisms of shuffling and perturbing. In this model, observational short-term precipitation data of Mehrabad station with a time duration of 10 minutes to 3 hours were used to predict short-term precipitation in the future. The results were compared with the output of the PRECIS regional climate model for the years 2070-2100 under emission scenarios A2 and B2. The results showed an increase in the intensity of future precipitation compared to the present time and moreover proved the capability of the WG model used in the study compared to the output of the PRECIS regional model. These results were evaluated using appropriate statistical tests.