Assessment of synoptic conditions of occurrence of flood-induced rainfall in Khalkhal city with a perimeter environmental approach during the time period 2016- 1987

y in Ardabil province analyzed the precipitation data of 30 years from 1987 to 2016. Most of the precipitation occurred on 09/12/1991.Synoptic atmospheric maps of this date at a level of 500 Millibars were prepared by sea level elevation maps, geopotential heights, wind speed and direction, humidity, temperature, perceptible water on ground level and blocking (omega), using satellite images from NCEP/NCAR databases which Affiliating to the National Oceanographic Organization of the United States. The research method is a circular environmental approach. The results showed that in addition to the ground and climate conditions that have been effective in causing heavy rainfall during this history, the internal situation with the external pattern, such as the seas around and adjacent to Iran like the Black Sea and the Mediterranean has been affected. The monthly precipitation of Khalkhal station as a region that is more prevalent in the south of Ardebil province and southwest of the Caspian Sea in the three months of the spring season is more than February (1321/8 mm), March (1716.7 mm) and April (1448 mm). The most natural atmospheric hazards affected by heavy rainfall and flood damage in Khalkhal, inland, village, river and agricultural damages occurred during these months.