Deriving surface motion of mountain glaciers in the Tuomuer-Khan Tengri Mountain Ranges from PALSAR images

摘要

Glaciers flow velocity is an important parameter for the study of glacier dynamics, mass balance and climate change, and can provide precursory warning of glacier melting induced flooding, debris flowing, etc. The Tuomuer-Khan Tengri Mountain Range is one of the largest glaciated areas in Tian Shan Mountain. However, the knowledge of glacier motion in this area is still rather limited. Using the method of robust Offset-tracking and four pairs of PALSAR images covering the Tuomuer-Khan Tengri Mountain Range, this paper estimates the displacement fields of the mountain glaciers in this area for each pair. The displacement fields are then mapped into daily glacier flow velocities by dividing the acquiring intervals of each pair. Using a series of checkpoints selected in stationary areas where the displacements can be assumed to be zero, we evaluate the estimation error of the displacement fields and find that most of them are less than 2.17 cm/day. The displacement fields are analyzed in detail with regards to glacier bed terrain and glacial temperature and thickness. We find that they are in excellent accordance with the flow characteristic of typical mountain glaciers. The velocity changes among the observation years have been carefully examined. This along with the associated runoff measurements makes us conclude that the glaciers in the Tuomuer-Khan Tengri Range are assumedly in dynamic equilibrium between intensified melting and increased precipitation and glaciation, and their velocity will maintain stable in the near future. We also find that the altitudes of the velocity peaks are close to the recorded snowline, which indicates that detecting the changes of velocity peaks' position might provide a reference for monitoring the changes of the snowlines.