Investigation of the Relationship between Snow Cover Persistency and Physiographic Characteristics of Watersheds (Case Study: Fasham Watershed, Latian Dam)

Snow accumulations of mountainous areas are the major and reliable sources of hydrological regime and streamflow in the warm seasons. Monitoring of persistency of snow covere area (SCA) in different months and melting process is important in the storage, drought management and forecasting of seasonal runoff. The major objective of this research is determining the relationship between SCA and physiographic parameters. For this purpose, Fasham Watershed was selected and its MODIS data was collected for 2004-2005 period. Then SCA and cloud mask were prepared using the spectral unmixing model in subpixel. In order to obtain of disappear date in each pixel, the watershed was resampled to 500*500 m grid. Physiographic features of each pixel such as elevation, slope and curvature were determined using the digital elevation model and its relationship was investigated with persistence of snow cover. The results showed that the highest and lowest correlation between persistency of SCA and mentioned parameters were attributed to elevation (88%) and slope (5%), respectively. On the other hand, there were weak correlation between aspect and curvature with persistence of snow cover.