The study of temporal and spatial distribution of storms and severe winds in Iran

According to world meteorological organization study، winds with more than 15m/s (30knot) are identified as storm. Therefore based on this threshold in this study، the temporal and spatial distribution of storms in Iran has been analyzed and zoning. In order to achieve the purpose of this study، after gathering the data of wind direction and speed in stations of the country، a common 40-year period among 33 stations was extracted، then regime of wind speed، storms frequency and direction were calculated with help of SPSS and EXCEL software. Then، the data was entered in Arc GIS software then، temporal and spatial distribution map of storms in Iran was obtained and analyzed. The results of this study show that، March had the most average stormy days with 12 days، in Zabol station، August had the most average stormy days with 26 days. The most frequency of storms occurrence was at 12 with 609 frequency. In zabol station most frequency storm was at 06 with 841 frequency.. Also، storm zoning shows that storms distribution in the country did not have fixed trend. In sum، Zabol station significantly had most frequency of storm occurrence. Zahedan، Kerman، Tabriz، Esfahan، Hamedan and Bandar anzali stations had high frequency occurrence. whereas، Khoram abad، Mashhad، Arak، Oromieh، Gorgan، Shahrud، Shiraz، Torbate heidarieh and Semnsn stations had the lowest frequency occurrence. The rest had the average storms occurrence. Also mean wind speed show that، in the more stations did not have significant relation between mean wind speed and frequency of storms occurrence.