Ecology, Environment and Conservation Paper

STUDY OF THE ATMOSPHERIC PARAMETERS CHANGE DUE TO THE CLIMATE CHANGE ON THE GAVEROUD RIVER RUNOFF USING SIMHYD MODEL

Moslem Nazari and Ahmad Rajabi

Abstract

The watershed is an open and complex system. Analysis and prediction of its behavior requires modeling by various statistical-mathematical methods. By formulating the greenhouse gas emissions scenarios by the intergovernmental panel on Climate Change, general circulation models with different assumptions have been used to predict the future climatic conditions. The simulated daily data for the future could be used as the input of hydrological models. As the first step of this study, the daily data of the minimum and maximum temperature of the Kermanshah synoptic station and the daily precipitation of the Shilan evaporative station in the period of 1967-2009 were simulated using Lars-WG statistical model. After ensuring of the model efficiency for predicting the mentioned hydrometeological data in Gaverod Basin, the data of three scenarios including A2, A1B and B1 and also HADCM3 model were compared to Lars-WG model in 2011-2030, 2045-2065 and 2080-2099 periods to investigate the impact of the climate change phenomenon on the study area runoff. Then, precipitation-runoff was simulated using the Simhyd model and the runoff changes due to the climate change in the future periods compared to the base period were calculated after calibration and validation of the model. According to the results, based on the Lars-WG estimation for the study scenarios in the future periods, the maximum and minimum temperature in the future periods will be increased significantly. The highest increase of the temperature occurs in the warm months (August, July and June). In some months the precipitation increase and in some other months decrease will occur. These changes are irregular. Generally, it could be said that the precipitation has increased in the summer and the spring and decreased in the autumn. Based on the results of the Simhydprecipitation-runoff model, The Gaveroud River runoff decreases in the winter and spring seasons and increases in the summer and autumn seasons than the observed period but generally except scenario B1, the runoff decrease occurs in the future periods.