Document Type : Research Article
PhD Candidate in Climatology, Faculty of Geography, Kharazmi University, Tehran, Iran
Faculty of Geography, Kharazmi University, Tehran, Iran
Atmospheric Science and Meteorological Research Center, Tehran, Iran
Water resources have experienced serious tensions in recent years due to climate change. The current study aims to investigate dynamical and statistical downscaling in order to downscale extreme precipitation in catchment of Gorganrood River over May13-14, 1992 which led to record the extreme discharge in this region. For this purpose, two models namely SDSM and Regcm4 were used. The results showed that SDSM has very low ability to simulate extreme precipitation so that the mean absolute error (MAE) was about 20 mm in the years 1983-2012 with very low coefficients of determination of 0.18 to 0.002, whereas Regcm4 model has recorded a very high coefficient of determination and mean absolute error of the model was about 67 mm. This model, however, could not well simulate Lazoreh station precipitation, because the model takes into account the overall dynamic patterns for simulation. Weather maps analysis indicates that low pressure patterns are dominant in the western half and parts of South and Central Iran in these two days. Direction of low pressure patterns is South and West from Adan sea and the Persian Gulf as well as the Black Sea and the Mediterranean Sea. Geopotential Maps show that low-height patterns are in 500 and 850 Geopotential height in this region.