Spatiotemporal analysis of snow cover in Iran based on topographic characteristics

Abstract

This study investigates the distribution of snow cover in Iran using the 8-day moderate-resolution imaging spectroradiometer (MODIS) snow product (MOD10A2) during 2001–2015. The year 2008 was found to have the most extensive snow cover and was used to determine the snow-covered areas into five regions based on topographic characteristics (elevation, slope, and aspect). Our results show that the mean snow cover extent (SCE) on the slopes higher than 20° is greater (62.94% on average) than on the slopes lower than 20° (55.28% on average). The highest and lowest SCEs are related to the north-facing aspect and flat-surface regions, respectively. In addition, a direct relationship between SCE and elevation was revealed, with snow cover reaching 100% in the highlands (above 3000 m). The highest values of the mean (171,905.1 km2 in slope1 from region 3), standard deviation (SD) (70,856.53 km2 in slope 1 from region 3), and coefficient of variation (CV) (214.65% in region 1) of SCE were obtained from 17 to 24 January, 9 to 16 January, and 10 to 17 February, respectively. The SD peaked in the early 8 days and then decreased in the middle and ending 8 days. The highest CV was obtained in the Caspian coastal region and decreased with increasing elevation.