Abstract
Knowledge about the occurrence and characteristics of surge-type glaciers is crucial due to the impact of surging on glacier melt and glacier related hazards. One of the "super-clusters" of surge-type glaciers is the mountains of Asia. However, no consistent region-wide inventory of surge-type glaciers in High Mountain Asia exists. We present a regionally resolved inventory of surge-type glaciers based on their behaviour across High Mountain Asia between 2000 and 2018. We identify surge-type behaviour from surface velocity, elevation and feature change patterns using a multi-factor remote sensing approach that combines yearly ITS_LIVE velocity data, DEM differences and very-high resolution imagery (Bing Maps, Google Earth). Out of the ≈ 95000 glaciers in HMA, we identified 666 that show diagnostic surge-type glacier behaviour between 2000 and 2018, which are mainly found in the Karakoram (223) and the Pamir regions (223). The total area covered by the 666 surge-type glaciers represents 19.5 % of the glacierized area in Randolph Glacier Inventory (RGI) V6.0 polygons in HMA. Across all regions of HMA, the surge-affected area within glacier complexes displays a significant power law dependency with glacier length. We validate 107 previously identified glaciers as surge-type and newly identify 491 glaciers. We finally discuss the possibility of self-organized criticality in glacier surges.
Highlights
Glacier surges are internally triggered, quasi-periodic oscillations of a glacier’s dynamical behaviour, alternating between slow 15 and fast flow (Meier and Post, 1969; Raymond, 1987; Sharp, 1988; Truffer et al, 2021)
We find no evidence of glacier surging in the Hengduan Shan or Dzhungarsky Alatau. 190 3.1 Distribution and geometry of surge and non surge-type glaciers Previous studies have demonstrated significant differences in glacier geometry between surge-type and non surge-type glaciers (see Sevestre and Benn (2015) among others, for example)
We here further document the impact of geometry on surge behaviour by studying glacier elevation range, slope, length area and aspect, using attributes derived from the Randolph Glacier Inventory (RGI) V6.0
Summary
Glacier surges are internally triggered, quasi-periodic oscillations of a glacier’s dynamical behaviour, alternating between slow 15 and fast flow (Meier and Post, 1969; Raymond, 1987; Sharp, 1988; Truffer et al, 2021). A substantial volume of ice is transferred from a reservoir zone down-glacier to a receiving zone. This mass transfer typically leads to drastic thinning in the upper reaches of the glacier and thickening at 20 lower elevations, often causing a substantial advance of the glacier terminus (see Sund et al (2009) for example). Glacier surges can occur on both polythermal and temperate glaciers In the former case, the bed can oscillate between cold and warm states over the course of a surge cycle, whereas in the latter the bed remains warm throughout.
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