عنوان مقاله [English]
As the first step, daily maps of synoptic system order of the region during July and August, the hottest months of the year, were investigated. The data belong to a statistical period (1993- 2014) extracted from the study center of NCEP/NCAR. Applying factor analysis test and clustering on web data, four synoptic patterns were recognized and the representative days of the patters were investigated. The aforesaid patterns present a similar patterns of the thermal equator and pressure systems in the region. The research results indicate that the Thermal equator is located in the south of Sahara in this time of year and it continues along the east, arid and low regions of the Arabia Peninsula, and the south of the Persian Gulf, Khuzestan plain, and Mesopotamia. Moreover, Gang low spread on the southwest of Asia also follows this pattern, as three main cores of low pressures are made on the low regions of Khuzestan plain and Mesopotamia, the south of the Persian Gulf, the north of the Arabia Peninsula and the center of Pakistan. This thermal belt on the lowlands of Mesopotamia (located in West Plateau of Iran) has the most intense and extending transverse and to be included from the northern half of the Iraq to southern part of Saudi Arabia. The thermal equator extends in the study area from the level 1000 to 850 hPa in accordance with the development of low Gang Tongue.