عنوان مقاله [English]
In this study, By studying the synoptic patterns of the lower levels of the atmosphere in the warm period (22 may – 22 sep) of Asia southwest (1996 – 2014), and Using factor analysis and clustering tests and also dynamical equations of convergence / divergence, vorticity and omega; an ridge of eastern winds (Iran ridge) was identified on the Iranian plateau, Which is part of the eastern winds caused by the deployment of India's Monson Trough in South Asia and the expansion of tongue from Ganges to the Asia southwest lowlands. Dynamic conditions of the atmosphere in the eastern part of Iran ridge, A nuclear of the divergence of the lower levels, Provide positive omega and air sinking and flowed eastward toward the west, and as the eastern winds flowing westward. At the same time, the dynamic conditions of the western part of Iran ridge, the nucleus of the convergence of the lower levels, Provide negative omega and climbing air that the flow of the mentioned wind pours into it. Then the air climbed in the western part of Iran ridge at the middle level, creates a core of high levels divergence and It flows to the west. With the arrival of this wind on the eastern half of Iran ridge, a core of higher levels convergence has created and with its descent into the lower levels divergence core in the eastern part of Iran ridge, Complete your cycle (Khorasan-Caspian Cycle). At the middle levels, there are also languages from Azores high on the region, the curvature of the northern part forms the ridge of western winds in northe of Iran and the Caspian Sea. The dynamic conditions of the west and east of this ridge caused the formation of negative core and positive omega that this, in turn, enhances the Khorasan-Caspian cycle.