Dynamics of surge‐type glaciers in West Kunlun Shan, Northwestern Tibet

Abstract

Here we examine 31 glaciers in the West Kunlun Shan of the northwestern Tibetan Plateau and identify 9 as surge type. The method is based on satellite synthetic aperture radar and Landsat optical images, the former going back to 1992, the latter to 1972. To identify surge-type glaciers, we consider temporal changes in velocity, changes in glacier terminus position, propagation of a surge bulge, presence of looped and/or contoured medial moraines, and extensive crevassing. Other than the nine surge-type glaciers, we identify two that have likely surged, and six that may be surge type. But no glacier surges more than once during the observation period, meaning that the recurrence interval exceeds 42 years. In addition, we examine the evolution of the surface velocities at two surging glaciers with the unprecedented temporal resolution of down to 11 days over ∼7 years. The results show clear seasonal modulations by as much as ∼200% in early winter against those in early summer. This seasonal modulation in surface velocity suggests the presence of surface meltwater that reroutes through the englacial and subglacial drainage systems. Thus, our findings suggest that the hydrological processes originating in the surface meltwater play an important role in maintaining the yearlong active surging phase.

The 2015 Surge of Hispar Glacier in the Karakoram

“…So, its surge mechanism might be different. A speed up in flow during winter was also observed by [38] for the West Kunlun Glacier, but we assume that the surge mechanism is different here as the glacier is at least poly-thermal if not cold based.…”

Hagen Bræ: A Surging Glacier in North Greenland—35 Years of Observations

“…In Greenland both types are found: Surging glaciers in East Greenland and Harald Moltke Bræ, Northwest Greenland were identified by Jiskoot et al () and Hill et al (), respectively, as Alaskan type while Storstrømmen Glacier and Bistrup Bræ show characteristics of Svalbard type (Mouginot et al, ). During both phases of a surge cycle, the flow may be modulated by the seasonal cycle or short‐term melt events (e.g., Flowers et al, ; Frappé & Clarke, ; Mansell et al, ; Yasuda & Furuya, ). On longer timescales climatic changes can significantly modify the surge cycle as projected by Mouginot et al () for Storstrømmen Glacier and by Hill et al () for Harald Molteke Bræ or terminate the surge behavior all together (e.g., Dowdeswell et al, ).…”

A Glacier Surge of Bivachny Glacier, Pamir Mountains, Observed by a Time Series of High-Resolution Digital Elevation Models and Glacier Velocities

“…Most detailed studies concentrated on the evolution of ice flow velocity during the surge (e.g., [15][16][17][18], with only few examples of time series of elevation changes during a surge (e.g., [19,20]). …”