forehead condition of the polar front in relation to the cold season on Iran

Abstract In this research, the seasonal behavior of polar jet streem has been identified based on the cold season (autumn and winter) on Iran. General analysis of jet streem process based on what is mentioned in the methods section was done in order to find the behavior patterns of jet streem in GRADS software environment . The results of the analysis indicate the existence of two main medium nuclei, one above Europe and a wider nucleus over North Africa and Saudi Arabia. The prevalence of nuclei in Europe has been higher than in North Africa. In autumn, the incidence of North African nuclei was about 30% lower than in Europe, and in winter the frequency of both nuclei was similar. The core of the polar jet streem in the two seasons, is located approximately 35 degrees north latitude. According to the information obtained from the average speed maps in autumn and winter, it seems that the speed change has been more than before.