A geomorphic and morphometric analysis of surface ice velocity variation of different valley type glaciers

摘要

Glacier surface ice velocity is one of the important parameters which determine the glacier dynamics. If the surface ice velocity is high in upper zone (accumulation zone) of the glacier, more ice is brought to the lower zone (ablation zone) of the glacier where it melts more rapidly. The surface ice velocity depends on multiple factors like geomorphology of a glacier and glacier valley, ice load, orientation of the glacier, slope and debris cover. In this study, we have used latest multi-temporal Landsat-8 satellite images to calculate the surface ice velocity of different glaciers from the Himalayan region and a relationship of velocity and geomorphology and geo-morphometry of the glacier has been studied. The standard procedure has been implied to estimate the glacial velocity using image to image correlation technique. The geo-morphometric parameters of the glacier surface have been derived using SRTM 90 m global DEM. It has been observed that the slope of the glacier is one of the main factors on which the velocity is dependent i.e. higher the slope higher is the velocity and more ice is brought by the glacier to the ablation zone. The debris cover over the glacier and at the terminus also affects the velocity of the glacier by restricting ice flow. Thus, observations suggest that the geomorphology and geo-morphometry of the glacier has a considerable control on the surface ice velocity of the glacier.