The uncertainty assessment of AOGCM & Hydrological models for estimating Gharesu basin temperature, precipitation, and runoff under climate change impact

In rainfall- runoff simulation of a basin under climate change, various uncertainties affect final results which would reduce reliability of the results if neglected. Also, overlooking uncertainties relating to climate change could exert unreal results for decision makers. In this research, we are trying to investigate the influence of uncertainty of rainfall-runoff and AOGCM models on Gharesu basin in 2020-2069 periods under A2 emission scenario. Nine AOGCM-AR4 models including; CCSM3، CGCM3، CSIRO Mk3، GFDL، GISS E-R، ECHAM5، HadCM3، MIROC-med، PCM and two conceptual rainfall-runoff models; SIMHYD, IHACRES were applied. At first, two rainfall-runoff models were calibrated for 1971-2000 periods. Downscaling the data of nine AGCOM-AR4 models for study area and introducing them to the rainfall-runoff models, changes of basin temperature, precipitation and runoff in 2040-2069 relative to the 1971-2000 was highlighted under A2 scenario. Results of this research showed that regarding uncertainties related to AOGCM and Hydrology models result in more accurate nomination in runoff modification in the area of study.