Geo-spatial dynamics of snowcover and hydro-meteorological parameters of Astore basin, UIB, HKH Region, Pakistan

Snowcover dynamics and associated accumulation and depletion of snowcover along with its spatial and temporal scale mainly constitute hydrological phenomena of the given basin and are mostly controlled by the local climate variables. Snow accumulation and melting time and duration determine the cyclic volume of water resources and downstream availability. In this study, snowcover area (SCA) was extracted from remotely sensed Moderate Resolution Imaging Spectroradiometer (MODIS) snow products (MOD10A2) for the period 2000-2016. Data for hydro-meteorological parameters was obtained from relevant departments acquired through their field stations. The analysis of 16-year satellite data shows that there is a slight increase in cryospheric area at high altitude. In Astore basin, the study concluded that 15-20% of the basin area is covered by glacier and snowcover may reach around 90-95% of the basin area due to accumulation of seasonal snow from the westerly wind circulation. Analysis of hydro-meteorological parameters showed significant correlation between temperatures (T-max, T-min) and river runoff while no significant correlation was observed between river runoff and rainfall. Similarly, significant inverse correlation was found between river runoff and Astore mean snowcover. At sub-altitudinal zone level (zones 1, 2, 3), river runoff has significant correlation with snowcover. Analysis of 20-year climate data along with river runoff depicts that river runoff is a general phenomenon of snowmelt when minimum temperature starts to rise above 4 A degrees C during mid of April. The study highlights the importance and interdependence of meteorological parameters and snowcover dynamics in determining the hydrological characteristics of Astore Basin.