Investigation of Variability and Trends in Number of Days with Snow Covers and snow cover depth in Iran during 1981-2010

This study investigates the changes and variability of the number of days with snow covers of ≥1 cm depth and the snow cover depth at 18 meteorological stations throughout Iran, spanning a period of 30 years (1981–2010) and 15 years (1996–2010). The studied parameters such as the number of days with snow cover; the snow cover depth and (mean, maximum and minimum) temperature was extracted from Iran meteorological organization data archive for December, January and February months. Investigation of spatial variability of parameters using GIS map shows that for the station with 30 years data, maximum number of days with snow cover and snow depth belongs to Abali station with values 2457 days and 80 cm in winter, respectively. But for stations with 15 years period data, maximum number of days with snow cover and snow depth belongs to Kohrang station with values 1346 days and 69.4 cm in winter, respectively. The results show significantee decreasing trend in time series of the days with snow cover and the snow cover depth at most stations except Kashan, Gorgan, Noshahr and Bandar Anzali stations in 30 years period while only in 5 stations such as Abali, Isfahan, Sanandaj, Tabriz and Urmia, increasing trend in temperature was observed also there wasn’t any trend in mean temperature in other stations.