Page - 525 - in Book of Full Papers - Symposium Hydro Engineering

3. RESULTS AND DISCUSSION 3.1. PROJECTED CHANGES IN TEMPERATURE AND PRECIPITATION Based on the results, three studied scenarios perform in a similar way during the first time horizon and two GCMs and applied scenarios suggest small temperature changes during 2020’s. However, temperature increases up to 1.2 and 1.1 °C is projected. While, based on all considered scenarios a significant rise in the average temperature is projected for 2050’s and 2080’s time horizons; as the average temperature in 2080’s is higher than the average of temperature during 2050’s. Generally, the B1 scenario suggests slighter temperature increase during 2050’s and 2080’s; while, scenarios A2 and A1B revealed a higher rise in temperature during these time horizons. HadCM3 revealed higher temperature increase during 2050’s, based on scenarios A1B, A2 and B1, respectively. But during 2080’s the highest rates of temperature for all the scenarios is suggested by ECHAM5. Assessing the magnitude of temperature variations from the base period, suggests that the maximum temperature increase is associated to 2080’s time horizon under the A2 scenario that shows an average increase of temperature between 3.6 to 4.4 °C in the study area. In a similar way, average of the projected precipitation for future time horizons based on two GCMs outputs and scenarios A1B, A2 and B1, show that most of the scenarios suggest increasing precipitation amounts compared to the base period. Also projections mostly suggest precipitation decrease in the first time horizon (2020’s) for Marbereh. Studying the percentage of variation of precipitation from the average precipitation amount in base period shows that, the greatest precipitation changes occur in 2080’s; that is mostly toward an increase in the amount of precipitation in the study area. Also, based on the projections, the highest precipitation increase is projected for the 2080’s tme horizon and especially for scenario A2. 525