Modeling of future decades changes of Irans precipitation as basic step in management for dry farming

摘要

Human being has a very significant and pivotal role in forming the environment behavior. The growing human population, emissions of greenhouse gas, changing the earth’s surface through building dams, etc cause great changes in the environmental system. The present research is an attempt to consider the changes in the rainfall and temperature in Iran in the coming decades influenced by the increase in the level of greenhouse gases. GFDLmodel was used for this purpose. For the simulation of changes in rainfall in Iran, 2025, 2050, 2075, and 2100 time scales were considered for the analysis. The results of the study showed that changes in the rainfall are incremental for cold seasons and decreasing in springs. Rainfall changes will also be incremental in summer. Furthermore, the simulated mean annual rainfall for 2025 in comparison with the long-term mean rainfall (1961 to 1990) shows a 30.09 mm increase in the level of rainfall in Iran. This increase is 52.83 mm in 2050, 43.75 mm in 2075, and finally 88 mm up to the year 2100. Areas like the North of Khorasan, North of Azarbayjan, North of Khorasan-e-Razavi and Golestan will experience the highest rate of decrease in the level of rainfall. On the other hand, areas such as the Eastern parts of the Persian Gulf and Bushehr, and north of Sistan-o-Baluchestan will have the highest rate of rainfall increase.