mahabad spring freezing forecasting, using synoptic study

the quality of pressure distribution over the atmosphere of the sea level and geopotential altitude at different atmosphere layers affect on many climate and meteorology phenomena of the earth surface. one of the important meteorology phenomenon is the occurrence of frost phenomenon especially late spring frost. in this surrey, occurring late spring frost days and minimum temperature during these days were determined using the minimum temperature statistic during the solar years 1364-1384 at mahabad meteorology station. moreover, the patterns of daily mean pressure distribution over the sea level atmosphere and atmosphere patterns at the layers 850, 700 and 500 hp in asia europe and the north of africa have been mapped and identified and the relationship between frost phenomenon occurrence in mahabad studied by atmosphere patterns at different atmosphere layers. the studies showed that there is a relationship among the incidence of spring frost phenomenon in mahabad and pressure distribution over the earth surface and atmosphere patterns at layers 850, 700 and 500 of hp in order that when forming and expanding the high-pressure center in east europe, the weather temperature decreases in mahabad and sometimes it goes down below water freezing-point. [a. gandomkar. mahabad spring freezing forecasting, using synoptic study. international journal of agricultural science, research and technology, 2011; 1(2):89-93].