Dynamics of glacier surface velocity and ice thickness for maritime glaciers in the southeastern Tibetan Plateau

Abstract

Influenced by climate warming, glacial hazards become increasingly frequent after glacier mass loss in the southeastern Tibetan Plateau. Investigations of mountain glacier surface velocities and volume are of great significance. However, no information is given regarding the specific changes in ice flow to climate warming, the spatiotemporal variations of glacier surface velocity and ice thickness are still unclear. In this study, offset tracking was used to measure glacier surface velocity in the southeastern Tibetan Plateau using Landsat TM/ETM+/OLI imagery from 1990 to 2018. And then spatially-distributed glacier ice thickness was estimated from mass-balance distribution data, glacier surface velocities and the principles of ice-flow. Results show that all maritime glaciers velocity in study area experienced a clear regional slowdown from 1991 to 2018, with robust overall trends of −5.26 m a−1 dec−1 (-19.8% dec−1) and 7.16 m a−1 dec−1 (25.2% dec−1) at elevations below and above 4 600 m a.s.l., respectively. Total volume for glaciers with an area of 954.34 km2 was found to be ~ 86.64 ± 11.09 km3 in 2013, corresponding to an average ice thickness of ~ 91 ± 12 m. The average ice thickness thinned by 0.62% a−1 during 2000–2013, and an accelerated melting can be expected in the long term and then glacier volume decreases more rapidly than in the last decades.