Synoptic-statistical analysis Heavy rainfall patterns in the Karkhe basin

Rain is one of the most important environmental variables that shows a lot of time and space changes And this phenomenon is affected by high-level circulation systems. Therefore, identification of dominant atmospheric patterns in relation to heavy rainfall is necessary to manage and reduce the risk of flood. in this research To identify heavy rainfall patterns In the Karkheh basin During the statistical period of 45 years(1967 to 2012) By applying 95 percent percentile On daily data 33 synoptic and Rain Sensing Through the approach environmental to Circulation Number of 310 days of heavy rainfall were detected then To explain the behavior of the patterns generating these rainfall By applying principal component analysis Of type T array And through promax rotation on Geopotential elevation dataof Exchanged from the National Center for Environmental Forecasting National Center of atmosphericResearch(NCEP/NCAR) Number 4 Weather brigade is identified. The results of this study were obtained showsWhich is the most heavy rainfallof Karkheh basin Affected by Deep Trough patterns Along with cut of low On the area and also Affected by have been from blockings of type Bipolar, omega, and Rex and And the study area in the eastern part of the Troughs that Formed by these patterns, is located.