Kermanshah Province and Precipitable Air Masses

Meteorological data of Kermanshah city in Iran and 13 cities over its North, East, and South sides set as temporal and spational daily mean tables according their latitude degrees. These tables availed us to knowledge cold and warm air masses. Then daily air maps at surface and 500 hPa level were used for synoptic patterns designing. These patterns present routes of Air Masses that have penetrated to Kermanshah province (AMKs). The results showed 5 types of AMKs including mP, cT, cP, mT, and mA from different origins have derived from general west toward Mediterranean basin and then they have entered to study area. It seems, the weakening of zonal index during transitional seasons causes the maximum diversity and frequency of AMKs. So, the minimum of diversity and frequency of AMKs accrued during summer and winter and it can be caused by the progress of cold air tounges of Siberian high pressure. The most percipitable AMK type was mP with 28 frequency. It originated mostly from England and they absorbed their moisture from Mediterranean Sea surface.Toward study area . During warm semester, the most frequent and precipitable AMK was mP and the least precipitable one was cP. Totally, AMKs during cold semester covered more study area southward in comparison with warm one.

کلیدواژه ها:

precipitable air masses ، synoptic patterns ، west of Iran ، Kermanshah province