A Surging Glacier Recognized by Remote Sensing on the Zangser Kangri Ice Field, Central Tibetan Plateau

Bowen Jia,Shugui Hou,Yetang Wang

doi:10.3390/rs13061220

Abstract

A glacier surge, which is quasi-periodic and involves rapid flow, is an abnormal glacier motion. Although some glaciers have been found to be surging, little is known about surging glaciers on the Tibetan Plateau (TP), especially the Central and Northern TP. Here, we found a surging glacier (GLIMS ID: G085885E34389N) on the Zangser Kangri ice field (ZK), Central TP, by means of the digital elevation models (DEMs) from the Shuttle Radar Topography Mission (SRTM), TanDEM-X 90 m, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) DEMs, and High Mountain Asia 8-m DEM (HMA), combined with Landsat images and the Global Land Ice Velocity Extraction from Landsat 8 (GoLIVE) dataset. This surge event was confirmed by the crevasses, shear margin, and visible advancing snout shown in the Landsat images produced since 2014 and the HMA. The inter-comparison of these DEMs and the surface velocity changes showed that the surge event started between October 2012 and January 2014. The glacier may have also surged in the 1970s, based on a comparison between the topographical map and Landsat images. The glacier mass balance here has been slightly positive from 1999 onward (+0.03 ± 0.06 m w.e.a−1 from 1999 to 2015, +0.02 ± 0.07 m w.e.a−1 from 1999 to December 2011), which may indicate that the ZK is located on the southern edge of the mass balance anomaly on the TP. Combining with other surging glaciers on the Central and Northern TP, the relatively balanced mass condition, large size, and shallow slope can be associated with glacier surges on the Central and Northern TP.

Highlights

Surging glaciers show quasi-periodic rapid motion [1]
The eastward-flowing glacier, G085885E34389N, showed an inverse elevation change pattern: the reservoir area thickened and the receiving area thinned in the difference map between High Mountain Asia 8-meter DEM (HMA) and Shuttle Radar Topography Mission (SRTM), as well as the difference map between ASTER digital elevation models (DEMs) and SRTM (Figure 2b–d), which can be a signal for a surge
Considering the limited coverage of ICESat points on glaciers on the Tibetan Plateau (TP), the erroneous mass balance result caused by the gathering of ICESat points on Zangser Kangri ice field (ZK), and the consistent mass balance results of ZK in this paper, we suggest that glaciers in ZK have had a slightly positive/nearly balanced condition since 2000 and ZK may be the southern edge of this glacier anomaly on the TP

Summary

Introduction

Surging glaciers show quasi-periodic rapid motion [1]. The cycle of a surge usually involves a short active phase with rapid movement and a long quiescent phase with slow velocity [2]. Glacier velocity is 10–1000 times higher in the active phase than in the quiescent phase. This rapid motion transfers a large volume of ice and snow downward, leading to thinning on the upper reservoir area and thickening on the lower receiving area, which is a characteristic of surges [3,4]. There are other indicative characteristics, such as crevasses, distorted medial moraine, and terminus advance [5,6]. Two major types of surges, the Alaskan-type and the Svalbard-type, are thought to have distinctions

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Discussion

Conclusion