Characteristic of spatial and temporal distribution of seasonal snow in Bayanbulak Grassland of Xinjiang Province

Snow is an important factor influencing the global climate and water balance. In this research, field observed data and remotely sensed images were combined to analyze spatial and temporal distribution of seasonal snow in Bayanbulak Grassland of Xinjiang Province. The inner-annual and inter-annual variation of snow was extracted from remotely sensed snow cover product (MOD10A2) of the Moderate Resolution Imaging Spectroradiometer (MODIS) from 2000 to 2010. Combining with digital elevation model (DEM) data, the distribution of snow cover in different terrain conditions were acquired. Impact factors influencing snow cover distribution in Bayanbulak Grassland were analyzed by correlation analysis of the distribution with the land surface temperature product (MOD11A2) and the NDVI product (MOD13A1).The results of the research showed that: (1) the mean snow cover fraction in Bayanbulak Grassland reached 45.6%. The snow cover fraction in 2000–2001 and 2007–2008 was higher than the others, and the fraction in January was the highest among the 12 months; (2) the snow cover frequency increased when the altitude increased, and it was higher in basin than in mountain area; (3) the analysis of spearman rank correlation showed that the snow cover fraction was negatively interrelated with the land surface temperature and the value of NDVI.