Distribution and Variation of Glacier Velocity in Himalayas based on ALOS PALSAR

Based on the 12 scenes ALOS PALSAR data from December 2007 to February 2010，combined with SRTM，we estimated the glacier velocityof the Himalayasin three periods by feature tracking method.The results show that glacier velocity of the winter of 2007，the summer of 2009 and the winter of 2009 were between 0~300 m·a^-1，and accumulation area of the glacier have obvious movement only in summer，butthe movement of the glacier tongue is obviousin any season.Long tongue glacier velocity decreasesslowlyalong the mainstream line，while the short tongue glacier velocity fluctuatesalong the mainstream line，and even increases.The glacier in east aspecthas the largest velocity.The glaciervelocity in southeast aspect and the southwest aspect are second，and glacier velocity is minimum in the north aspect.In addition to climatic factors，it also closely relates to terrain factors.In terms of the slope of the four aspects，the north aspecthas the smallest slope，andit is one of the main causes of the smallest glacier velocity in the north aspect.There is an inter-annual variation of glaciers，that is，mean velocity of glaciers increases in winter，and the increased velocities are between -5~18 m·(2a).The glacier with small areavaries greatly，and the glacier with large area varies little.Meanwhile，the glacier velocity also has seasonal variation.The overall velocity in summer is larger than that in winter.The velocity in mainstream line fluctuates strongly in summer，and there are many peaks，but velocity in winteris gentle.However，the seasonal variation of the mean velocity in mainstream line is not obvious.The inter-annual variation and seasonal variation of the four typical glacier velocities are similar to those of the glaciers in the study area.There is a close relationship between velocity and climate and the shape of the glacier.The characteristics of glacier advance and retreat are not obvious，and the glaciers in the study area are in equilibrium.