تحليل الگوي سينوپتيكي بارش سيل زاي پاييز سال 1382 سواحل جنوبي درياي خزر

Analyzing Synoptic Pattern of 20th October 2003 Flood in the Southern Coastal Areas of the Caspian Sea

In this study the synoptic patterns of the 20th October 2003 flood in the southern coastal areas of the Caspian sea especially in the Mazandaran and Gilan provinces have been investigated. For this purpose considering geographic conditions and physical characteristics of the southern coastal areas of the Caspian Sea weather maps and daily and hourly(3 hours interval) meteorological data of each synoptic stations have been qnalysed. During a 8 days period(14th -21st October 2003) the Synoptic patterns arrangement and their trend investigated using weather maps including surface, 850, 700 and 500 hpa levels. The results show that presence of a deep trough in the northeast of Europe and itʹs axis orientation on the Caspian sea has been caused the polar air(C.P) advection from northern-latitudes on it. Also it has been amplified by presence of a transition anti-cyclone with northwest-south orientation in the west of the trough and frontal cyclone in the east of the trough and because similar orientation of western anti-cyclone rotation and eastern part of the ahead trough cyclone. On the other hand vorticity has been amplified by considerable meridional motion of the middle level tropospheic flows. Simultaneity with these factors and also intensification of maximum temperature difference between the polar cold air and Caspian sea water in this season are factors that causing the mentioned intense rainfall.