Evaluation of a dynamical downscaling climate model for assessment of climate change in Karkheh Basin

The increase of greenhouse gases caused imbalance in the amount of air and water in the Earth, which called climate changed. Increasing the greenhouse gases not only impact on the weather parameters, but also impact on water resources, agriculture, environment, health and the economy as well. For the effects of climate change on different systems in the future, first the climatic variables which are affected under the greenhouse gases should be simulated (different climate scenarios). There are several simulation methods where the climate model methods are most suitable. The AOGCM model is able to simulate global climate in large scale, while not suitable for small and regional scale. So, it is necessary to identify the variations (climate) in small scale. For this reasons it is necessary to use the downscaling methods such as dynamic methods which are based on high resolution and analysis of climate models. This method is suitable and appropriate for Iran since it suffers from lacks of observed data as well as lack of long term and enough stations in the country. In this study, PRECIS model (a dynamical downscaling climate model) was evaluated for simulation of precipitation and temperature. In general, the results of PRECIS model indicate this model can be a good estimate of temperature and precipitation in the region. Although for the rainfall in autumn and spring, due to the local nature of the precipitation, the model is not very strong. Also, comparison of spatial and point evaluation of the model showed that areal evaluation is appropriate as opposed to a point.