Large warm advection over athens: a climatological and synoptical study
Tóm tắt
In the present paper, warm air advection in the Greek area as a precipitation causing factor, is examined. A total of 125 large warm advection (L.W.A.) cases, were selected. From the mean synoptic charts it is observed that L.W.A.'s are a result of the eastward movement of a system of two depressions, separated by a high. The first depression is located over the eastern Mediterranean and the second over the eastern Atlantic. A superposed epoch analysis was applied to the precipitation amounts as well as to precipitable water and to the saturation deficit of the 1000/500 mb layer, during L.W.A. events. No appreciable precipitation amounts were found during the 48 hours of L.W.A. From the above analysis as well as from the calculations of the Showalter stability index it is concluded that the scarcity of precipitation in the south Greek area during L.W.A's should be attributed to diabatic heating and static stability, counteracting warm advection and caused by a field of downward vertical velocities.
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