Analysis of Annual Changes of Subtropical High Pressure Ridge over Iran

Atmospheric circulation is a fundamental factor in determining the climatic conditions of every region (Mofidi and Zarrin, 1391). Therefore, the climate framework of every location is based on large-scale systems. One of the most obvious and permanent tropical landscapes along the northern and southern tropical hemisphere as cores of high-pressure centers or high-altitude bands is called the "tropical high-pressure" system. The subtropical high-pressure cores are known in various areas under various names (such as high-pressure azure, high-pressure Saudi, etc.). For example, Mason and Anderson (1963) define the most intense and permanent anticyclone as the Asian Anticyclone studying the two levels of 100 and 50 hPa and by investigating daily weather-condition maps during 1957-59. Since the spatial-temporal variance and intensity change of this system causes anomalies in regional and global circulation and consequently climatic anomalies, therefore, due to the geographical location of Iran relative to the climate of the above system, the spatial variations of this system have significant effects on Iran.