Identification and Interpretation of a Surge-type Glacier in the Central Tibetan Plateau with Multi-source Satellite InSAR Datasets

Abstract:

Surge-type glaciers are very important to understanding of glacier dynamics and mass balance. They generally experience well-defined cyclical non-steady flow, with alternation between short active phases (months to years) and a longer quiescent phase (years to decades). Previous studies reported that most of surge-type glaciers in the High Asian Mountain were detected in the Himalayas and Karakoram, however, few studies were carried out in the central Tibetan Plateau (TP).

This study is focused on identification and characteristics of surge-type glaciers by using satellite InSAR technique on the Puruogangri Ice Field (PIF) in the central TP, the largest modern ice field over the TP. Firstly, a very high-resolution DEM was retrieved by applying bi-static InSAR to a pair of TerraSAR-X/Tandem-X data in 2012, then elevation changes were estimated by subtracting SRTM-X DEM (2000) from it. Secondly, bi-temporal surface velocities were measured by D-InSAR technique with a pair of ERS tandem data in 1996 and a pair of ALOS PALSAR data in 2009.

The preliminary results of elevation changes show that a significant thickness increase of approximate 70 meters was detected at terminus of the glacier (WGMS id: 5Z213E0012) between 2000 and 2012. In particular, an analysis of glacier elevation changes with altitude exhibits that this glacier experienced a surging before 2012. Moreover, the results of surface velocity demonstrate that the ice-flow velocity amplitude of this glacier was relatively slow with average values of about 3.5 m/yr in 1996 and 3.0 m/yr in 2009. A synergistic analysis of the changes in elevation and velocity infers that the glacier surge event might occur between 1996 and 2009. But at the present we could not make sure of its exactly active and quiescent phase, and further studies are required.