Investigation of the atmospheric structure of the foehn phenomenon at the time of forest fires in northern Iran Case study: January 25-31, 2007

In order to investigate the atmospheric mechanisms governing the occurrence of the Von phenomenon at the time of forest fires in northern Iran, four types of data were used in the research. First, by taking the statistics of fires, the forests of the north of the period were identified. The monitored data of temperature, pressure, and wind in the front and back slopes of the Alborz mountain range were examined, as well as the networked data related to the National Environmental Forecasting / Atmospheric Science Centers (NCEP / NCAR). The European Center for Atmospheric Prediction (ECMWF) was used to explain the structure of the atmosphere. Modis sensor images were used to investigate the surface temperature and a suspended particle regression model was used to track the air mass. Studies have shown that with the formation of hypertension in the south of the country and low pressure in the north of the Caspian Sea, a strong pressure gradient is created and causes the southern currents in the northern regions of Iran to be affected. So that with the rising of the air mass on the Alborz mountain range and evacuation of its moisture and then passing the air package over the mountain and the heatless heat resulting from that hot and dry air mass has entered the region, these conditions are accompanied by strong winds and areas Susceptible to fire. Studies show that there is a sharp temperature difference between the windward and backward areas of the mountains, which is due to the unreasonable decrease and increase of air closure in the region. Airborne tracking also indicates that the main source of current entering the region is in the northern Persian Gulf and Northeast Africa.