Asejiaguo Glacier drains east from the China-Nepal border and is at the headwaters of the Yarlung Tsangpo, which becomes the Brahmaputra River. The Yarlung Tsangpo powers the 510 megawatt Zangmu Hydropower Station. Gardelle et al (2013) identified this glacier as part of the West Nepal region, which experienced mass loss averaging -0.32 meter/year from 1999-2011. The changes of the Asejaguo Glacier are examined for the 1993 to 2018 period using Landsat imagery. Neckel et al (2014) examined changes in the surface elevation of the glaciers and found this region lost 0.37 m/year from 2003 to 2009.
In 1993 the glacier terminated in a small proglacial lake that is ~1 kilometer long at 4,900 m. At Point 1-2 there is limited exposed bedrock at 5,400-5,600 m, which is near the snowline; the head of the glacier is at 6,000 m. There is a prominent medial moraine that begins at 5,300 m where the north and south tributaries join. The greater width of the southern tributary indicates this is the large contributor. In 1994, the snowline is higher, at 5,500 m, but there is still only a small outcrop of bedrock at Point 2. By 2016 the proglacial lake has expanded to a length of over 2 km. At Point 1 and 2 there is a greatly expanded area of bedrock and the separation of a former tributary near Point 1 from the main glacier. In November 2018 there is fresh snowfall obscuring the exposed bedrock at Point 1 and 2. The retreat from 1993-2018 is 1.5 km, and the expanding proglacial lake is over 2.5 km long. The expanding bedrock areas in the 5,400-5,600 m range indicate the reason rise in snowline that has generated mass loss and ongoing retreat.
This article originally appeared on the American Geophysical Union blog From a Glacier’s Perspective.
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