بررسي و پيش بيني تغييرات دما و بارش در ايران

Review and Prediction of Temperature and Precipitation in Iran

At the first stage of this study climatic data of the 41 synoptic stations of Iran were considered using "Cluster Analysis" method and then five homogenous climatic regions were determined on the basis of obtained results. At the second stage five representative stations were selected for each climatic regions. Variations of the minimum and maximum temperature and monthly total precipitation from 1966 to 1995 were examined using "Seasonal Autoregressive Integrated Moving Average" (SARIMA) method. A stochastic model was developed for each representative station. The innovation variance and "F" test were applied for detecting variabilityʹs of the climatic factors considered in this study. The results obtained show that the variability of climatic factors was not evenly distributed throughout the study period. In other words, minimum temperature in the northern regions (Caspian Seashore) and mountainous areas comparing the other parts of the country has significant differences and maximum temperature in the vast areas of the country except the southern parts (Persian Gulf and Oman Seashores) has detected significant variation. On the other hand, monthly total precipitation doesnʹt show significant statistical variations except for the margin areas of central deserts. Lack of trends in considered climatic factors is in line with other similar researches.