Investigation of AOGCM Model Uncertainty and Emission Scenarios of Greenhouse Gases Impact on the Basin Runoff under Climate Change, Case study Gharanghu Basin, East Azerbaijan

This research was aimed to investigate the changes of runoff considering the uncertainty of AOGCM models and emission scenarios that may occur due to climate change in the period of 2010-2039 (2020s). First, the monthly temperature and precipitation data of AOGCM models (models of TAR reports) were provided for the baseline period (1971-2000) and the future period (2010-2039) under the SRES emission scenarios, namely A2 and B2. Then, these data were spatially and temporally downscaled to Gharanghu basin by proportional and change factor methods. Results showed that the temperature increased and the precipitation decreased in the future compared to the baseline period. The monthly probability distribution function of the temperature and the precipitation in the period of 2020s was constructed using weighting method; comparing observed and modeled temperature and precipitation. A semi- conceptual model (IHACRES) was calibrated for simulation of the monthly runoff of the basin. Using the Monte Carlo approach, 2000 samples of temperature and precipitation were generated by the probability distribution functions and were introduced to IHACRES. Finally 30-year time series of monthly runoff were simulated in 2020s. The results were compared to the baseline result which indicated that the climate change will affect the runoff in the basin.