Recognition the circulation patterns of flood generating heavy precipitations on the Fars region

Recognition the circulation patterns of flood generating heavy precipitations on the Fars region : Flood generating heavy precipitations is one of the most destructive natural disasters that have historically done heavy harm to people. Hence, the main aim of this synoptic study is to explain key interactions between the atmosphere and surface environment and in other words exploration of the relationship between the circulation patterns leading to the heavy precipitations on the Fars region in order to predict of the occurrence showers that lead to flood. In order to recognition and analysis the circulation patterns of flood generating heavy precipitations of Farvardin, 1391 on the Fars region was used of 24 rain gauge stations data. Then, the 6-hour and daily NCEP/NCAR 2.5*2.5 reanalysis data of sea level pressure, geopotential height, specific humidity and zonal and meridional wind components at different levels from two days before of precipitation days were employed and on the basis of environment-to-circulation approach are studied. The results revealed that the existence of a cyclone was the main mechanism of precipitation on the Fars region. However, results indicated that flood generating heavy precipitations occurrence on the Fars region are caused by dominance of deep trough on the Black Sea and southern Mediterranean at 500 hPa level. Analysis of the moisture flux convergence patterns also have shown that heavy precipitation are caused by moisture flux of water masses of the Persian Gulf ,Arab Sea and Red Sea.