Synoptic and Hydro Meteorological Detection of Meteorological Roots of Heroo Chay Flood

Floods are one of the most destructive atmospheric hazards which push different communities all over the world to suffer from life and financial damages. The present research has the aim of detection of synoptic and hydrometeorology features of flood in Herochay. For this goal, the data from daily rainfall of stations in Khalkhal, Khanghah, Arpachayi and Lamber and the data from Hydrometer station in River Kivichay was used to detect the rainfall and flood happened and for synoptic inspection of this phenomenon, the data from Sea level pressure, upper layers of atmosphere like Geopotential high, Omega, Orbital wind, Meridional wind and Relative humidity in levels of 500 to 1000 HPA was used. The obtained results show that presence of low-pressure system on the surface of ground, occurrence of blocking and located of the study area on the east of the trough on the upper levels, negativity of atmospheric eddies and omega on different levels with humid supply of Black Sea and Mediterranean sea on the levels of 500 to 700 HPA, Red sea and Persian Gulf and Oman Sea on the levels of 850 and Caspian Sea on the levels of 925 and 1000 HPA have prepared the conditions needed for generation of instability over the atmosphere of the studied area. The mentioned conditions have caused intense thunderstorm and increase of Herochay discharge and generation of flood in that region.