Tag: china glacier retreat lake expansion

Duiya Glacier, China Retreat Drives Lake Expansion

On By mspeltoIn china glacier retreat1 Comment

Duiya Glacier, China in 1990 and 2017 Landsat images.  Red arrow indicates 1990 terminus, yellow arrow the 2017 terminus, pink arrow the terminus area of Duosangpuxi purple dots the snowline

Duiya Glacier, China is in the Pumqu Basin northwest of Mount Everest.  The glacier terminates in an expanding lake.  King et al (2018) report the proglacial lake is dammed by a full moraine loop, and the glacier loses mass via calving as and surface melt.  Here we use Landsat imagery to identify changes from 1990-2018. The Pumqu River becomes the Arun River in Nepal , which has a proposed 900 MW hydropower plant under development .

In 1990 the glacier terminated in a small proglacial lake, 500 m across at 5500 m.  The snowline in 1990 was at 6000 m.  The Duosangpuxi Glacier to the east also terminates in a proglacial lake.  In 2000 the lake has expanded to 800 m in length due to retreat.  The glacier snowline is at 6000 m again.   The Duosangpuxi Glacier to the east has retreated from the lake it formerly terminated in.  By 2017 the glacier had retreated 1020 m a rate of 37 m/year. The lake is now over 1.5 km long.  The snowline in 2017 is at 6200 m.  In September 2018 the snowline has likely not reached its highest elevation but is just below 6200 m.  The terminus is obscured by clouds, but has not changed significantly from 2017.  There icebergs in the lake indicating calving continues.  The high snowline in recent years indicate continued mass loss that will drive further retreat.

King et al (2017) examined the mass balance of 32 glaciers in the Everest region for the 2000-2015 period including the Duiya and found a mass loss of ~0.5 m/year, with the loss of lake terminating glaciers at ~-0.7 m/year.  The retreat of this glacier is like that of Yanong Glacier and Chaxiqudong Glacier whereas Rongbuk Glacier has experienced supraglacial lake expansion, and thinning without as much retreat.

Duiya Glacier, China in 2000 and 2018 Landsat images.  Red arrow indicates 1990 terminus, yellow arrow the 2017 terminus, pink arrow the terminus area of Duosangpuxi purple dots the snowline.

Broader view of the Duiya Glacier (Du) and neighboring glaciers Cuolangma (C) and Duosangpuxi (Dx), each terminating in a lake in 1990. 

Yanong Glacier, Tibet Retreat Lake Expansion 1992-2017

On By mspeltoIn china glacier retreat

Yanong Glacier and North Yanong glacier in Landsat images form 1992 and 2017.  Red arrows indicate 1992 terminus and yellow arrows the 2017 terminus. 

Yanong Glacier  and North Yanong Glacier drain northwest from the western flank of Cho Oyu on the Nepal-China border and are in the Tama Khosi watershed.  The glacier terminates in an expanding proglacial lake like a number of neighboring glaciers Drogpa Nagtsang, Rongbuk Glacier and Lumding Glacier.  King et al (2017) observe that both Yanong and North Yanong have had large negative balances of -.76 m/year and -0.62 m/year respectively.  They also note surface lowering of 3 m per year in the lower ablation zone.  Zhang et al (2010) observed the loss of glacier area and lake expansion in the region from 1976-2006. Here we examine Landsat imagery from 1992 to 2017 to observe changes.

In 1992 the Yanong Glacier and North Yanong Glcier terminate at the red arrows.  The proglacial lake at Yanong is 1.7 km long and is 1.3 km long at North Yanong. By 2001 significant retreat of 200-200 m has occurred on each glacier.  By 2015 Yanong Glacier has retreated east of the a former tributary from the north. The North Yanong glacier is now wider at the terminus than in 2001. In 2017 the proglacial lake at Yanong Glacier is 2.8 km long indicating a retreat since 1992 of 1100 m.  The North Yanong Glacier proglacial lake is 2.1 km long indicating a retreat since 1992 of 800 m.  The steep crevassed nature of North Yanong Glacier right to the terminus suggests the glacier is nearing the end of the lake basin.  The Yanong Glacier has a low slope terminus area that suggests the lake will continue to expand.  The Upper Tamakoshi Hydropower project is a 456 MW peaking run of river  is a hydropower project on the Tamakoshi that is just to be finished in 2018.

Yanong Glacier and North Yanong glacier in Landsat images form 2001 and 2015.  Red arrows indicate 1992 terminus and yellow arrows the 2017 terminus. 

Digital Globe image of Yanong Glacier note the low slope terminus tongue below steep crevassed icefall section, red arrows.

Digital Globe image of  North Yanong Glacier note the l steep crevassed icefall section, red arrows that leads right to the terminus.