Zhizhai Glacier Retreat, Lake Expansion, China

On October 29, 2015May 2, 2024 By mspeltoIn china glacier retreat, climate change glacier retreat

Fig. H. Zhizhai Glacier change from 1991 to 2015, red arrow indicates 1991 terminus, yellow arrow 2015 terminus and purple arrow indicates areas of thinning. Green arrow indicates another lake growing with glacier retreat.

Located between Longbashaba Glacier and Jimi Glacier, this glacier extends 4.75 km north from the Nepal-China border in the southeast region of the Pumqu River basin. The moraine dammed glacier lake, Zhuxico Lake, poses some risk to the 23 villages downstream of the lake and the Rongkong Hydropower station. This risk has been examined for another lake in the basin Longashaba by Yao et al (2012). Che et al (2014) report on an inventory of glaciers and glacier lakes in the Pumqu Basin, and note that lake expansion is higher from 2001-2013 than for the 1970-2000 period, posing greater threats for a glacier lake outburst flood. They report that there are 254 glaciers lakes in the basin currently 55 of which have formed since 1970. In 1991 the glacier terminated in a proglacial lake that was 2.25 km long. A tributary flowed around a ridge and rejoined the main glacier, purple arrow. By 2000 the glacier had retreated 200 m, the tributary at the purple arrow remains connected to the main glacier. By 2015 the glacier had retreated 600 m and the lake is 2.9 km long and remains 300 m wide. The tributary at the purple arrow no longer rejoins the main glacier. Just east of Zhizhai Glacier an unnamed glacier also features an expanding lake due to glacier retreat (green arrow). The retreat follows the pattern of other glaciers in the region that are retreating and having glacier moraine dammed lakes expanding such as Longbashaba Glacier and Lhonak Glacier.

Landsat image 2000

Google Earth Image indicating the flow of the glacier, blue arrows and areas of upglacier thinning, purple arrows.

1991 to 2015 Comparison

Midui Glacier, Tibet, China: Retreat and Terminus Collapse 1995-2014

Midui Glacier is 7 km from the G318 National Highway in China and 2 km from Midui village, hence the lake near the terminus is often visited. The glacier is near the headwaters of Yarlung Tsangpo. Glaciers in this region have experienced significant retreat and area loss as noted by the second China Glacier inventory. This compared glacier area from the 1950’s, 2002 and 2010, Liu et al (2013) noted that glacier area has declined 13%. The Midui Glacier was advancing as recently as 1964 when it emplaced an advance moraine (Xu et al, 2012). This is a region where Li et al (2011) noted that increasing temperature, especially at altitude, the fronts of 32 glaciers have retreated, mass losses of 10 glaciers have been considerable, glacial lakes in six regions have expanded and melt water discharge of four basins has also increased. This is further documented by an inventory of 308 glaciers in the Nam Co Basin, Tibet, where an increased loss of area for the 2001-2009 period, 6% area loss (Bolch et al., 2010) was observed. The nearby Yemayundrung Glacier retreat is similar. Here we examine changes in this glacier using Landsat imagery and Google Earth from 1995-2014.

1995 Landsat image

2014 Landsat image

In the Landsat images above in 1995 the glacier terminates in a proglacial lake at the red arrow. A ridge separates two tributaries each with an icefall creating ogives, purple arrow. There are ogives below a pair of icefalls at the yellow arrow. The tributaries are separated by a medial moraine orange arrow. By 2014 retreat has led to expansion of the lake at the terminus. The retreat is 300 meters during this 20 year period. The icefall on the right, east side of the glacier, is no longer producing significant ogives and the bare glacier ice has been replaced with extensive debris cover, yellow arrow. Both the ridge and medial moraine separating the tributaries have expanded in width as the glacier has thinned.

A series of comparison images from Google Earth in 2001 and 2014 further illustrate the changes noted above.

In the first pair the terminus change and lake expansion is evident at the red arrow. Debris cover expansion at the lateral moraine area with thinning of the eastern tributary is notable at the yellow arrow.

The second pair is the terminus reach. A series of depressions are noted with each yellow arrow, indicated by concentric crevassing. This indicates collapse due to a subglacial basin/lake. Further this indicates a stagnant collapsing terminus area in the lower 1.5 km of the glacier.

The last pair is the icefall region indicating reduced crevassing below the lefthand icefall, pink arrow and the expanding medial moraine yellow arrow. It is clear that this glacier is going to continue to retreat in the coming decades, and the rate is going to increase in the near future as the collapsing sections of the terminus melt away. There is still considerable glacier area that remains snowcovered each year, and it can survive current climate and some additional warming. The snowline on the glacier is at 5000-5100 m and the head of the glacier is at 6100 m.

Midui Glacier comparison from Google Earth

Midui Terminus comparison from Google Earth

Midui Icefall comparison from Google Earth

Menlung Glacier Rapid Retreat & Lake Expansion, Tibet, China 1992-2014

On April 13, 2015May 3, 2024 By mspeltoIn Himalaya glacier retreat

Menlung Glacier is one valley north of the China/Tibet border with Nepal and on the south side of Menlungste Peak. Menlung Glacier has a glacier lake at its terminus that is dammed by the glacier’s moraine. The glacier began to withdraw from the moraine and the lake began to develop after the 1951 expedition to the area. The glacier lake is at 5050 meters, the glacier descends from 7000 meters with the snowline recently around 5500 meters. The lower section of the glacier is heavily debris covered, which when the debris is more than several centimeters thick as in most areas here, reduces the rate of glacier melt. Melt is highest around the supraglacial lakes (shallow lakes on glacier surface), which can lead to the lakes expanding and coalescing. Benn (2001) examined the process on nearby Ngozumpa Glacier, Nepal. This region has experienced significant mass loss of -0.25 m/year from 2000-2010 (Gardelle et al, 2013). The Japanese Aerospace Exploration Agency has a side by side 1996 and 2007 satellite imagery that indicates the Menlung Glacier Lake developing in 1996 that still has remnant glacier ice in it, that is melted by 2007. Here we use Landsat imagery and Google Earth imagery to identify the changes from 1992-2014.

1992 Landsat image: In each image the pink arrow is the 1992 terminus, the yellow arrow the 2014 terminus, the green arrow the furthest downglacier extend of clean glacier ice and the red arrow the lower margin of a tributary glacier in 2014.

In Landsat imagery from 1992 the lake is still developing from a system of supraglacial lakes interspersed with debris covered stagnant glacier sections. In 1994 there is little change, other than some of the lakes are frozen. In 2001 a contiguous lake has formed that is 500 m long and 600 m wide, though the main glacier front has changed little. The lake rapidly expanded to a length of 1900 meters by 2009. The glacier retreat is 500 meters, the other 300 meters of lake expansion is a continued growth at the moraine end of the lake as ice cored moraine continues to melt. By 2013 the lake has extended to a length of 2250 m, due solely to further glacier retreat. In 2014 has experienced a further 50-100 m of retreat from 2013. The lake is now 2300 m long, and is turning a darker blue color as the amount of glacier flour in it diminishes. A comparison of the terminus and lake using Google Earth images from 2005 and 2014 indicate the rapid lake growth in the last decade. The lower portion of the glacier remains debris covered, and appears stagnant, but has significant supraglacial lakes only with 400 meters of the 2014 terminus, suggesting the period of rapid retreat is nearly over. The region above the terminus in 2014 is dissected by a significant surface glacier stream that extends 2.5 km upglacier to the beginning of the first sections of debris free ice. That the river stays on the surface so long indicates the lack of crevassing and the stagnant nature of the ice. From 1992 to 2014 the area of clean glacier ice has also migrated 1 km upglacier, green arrows. The red arrows indicate a smaller glacier that has retreated further from the lake and has developed some substantial bedrock areas amidst the lower glacier between 1992 and 2014. The retreat and lake expansion parallels that seen at Longbasba, Reqiang, Sepu Kangri and Ngozumpa Glacier.

1994 Landsat image

2001 Landsat image

2009 Landsat image

2013 Landsat image

2014 Landsat image

2005 and 2014 Google Earth image comparison

2014 Google Earth images. Black arrows indicate supraglacial stream.

Ribuktse Glacier Retreat, Tibet, China 1991-2014

On October 19, 2014October 19, 2014 By mspeltoIn Glacier Observations1 Comment

Ribuktse Glacier drains east from 6200 m peaks along the Nepal-China border. The glacier ends in a lake that drains into Ribuktse Tso, the Yarlung Tsangpo (Zangbo), which becomes the Brahmaputra River. The Zangmu hydropower project is being constructed on the river, it is a 510 MW project. Here we examine Landsat and Google Earth imagery from the 1991-2014 period. This is a region where Li et al (2011) noted that increasing temperature, especially at altitude, the fronts of 32 glaciers have retreated, mass losses of 10 glaciers have been considerable, glacial lakes in six regions have expanded and melt water discharge of four basins has also increased. Neckel et al (2014) examined changes in surface elevation of the glaciers and found this region lost 0.44 m/year from 2003 to 2009.

Google Earth image

In 1991 the glacier ends in a proglacial lake at the red arrow, the yellow arrow is the 201 terminus. The lake at an elevation of 5050 m is 1.1 km long and 600 m wide. The purple arrow indicates two tributaries that connect to the larger valley glaciers. By 1998 the lake has expanded. The tributary to the glacier to the north of Ribuktse has separated from the main glacier. In 2000 and 2001 the tributary to the Ribuktse Glacier is still connected to the main glacier. The terminus continues to retreat with lake expansion. By 2005 the lake is 1.8 km long and the tributary is no longer visibly in contact with the main glacier at the purple arrow. In 2014 the terminus has retreated 800 m since 1991, the lake is 1.9 to 2 km long and the tributary has significantly separated form the main glacier. At the glacier just to the north the tributary separation from the valley glacier has led to a new glacier lake developing by 2011. There is little evidence of calving from Ribuktse Glacier. The retreat of the low slope glacier tongue in the proglacial lake lacking calving will continue at a slow rate. The high elevation of the glacier terminus area limits the magnitude of ablation on the glacier tongue. The retreat follows the pattern of the Yemayndrung Glacier just to the south, Durung Drung Glacier, India, Reqiang Glacier, China and Matsang Tsanpo Glacier, China which are in a similar climate setting. This area did get an unusual heavy October snowfall from Cyclone Hudhud this week.

1991 Landsat image

1998 Landsat image

2000 Landsat image

2001 Landsat image

2005 Google Earth image

2014 Landsat image

2011 Google Earth image

Hailuogou Glacier Retreat, China

On December 29, 2011December 29, 2011 By mspeltoIn Glacier Observations

The Hailuogou Glacier has retreated 1.8 km during the 20th century. This glacier drains southeast from Gongga Shan beginning at 7500 m and extending to a debris covered terminus at 3000 m. The first image is a map from Li et al (2010).The glacier has been the focus of an ongoing research program by the Laboratory of Cryospheric Sciences, Chinese Academy of Sciences, Lanzhou, China and Nagoya University, Japan. This glacier is a summer accumulation type glacier fed largely by the summer monsoon. The glacier feeds the Dadu River. which eventually joins the Yangtze River. The Dadu River has a series of hydropower plants that fed in part by the glaciers of Gongga Shan. The Pubugou Hydropower Station has a total generating capacity is 3,300 MW, Gongzui Hydropower Station 600 MW and Tongjiezi Hydropower Station 700 MW and the still under construction Dagangshan Hydropower Station 2600 MW. The main changes in the Hailuogou Glacier are the continued thinning of the ablation zone, not terminus retreat of the heavily debris covered terminus. The terminus is at 3000 meters (T), the debris cover dominates to 3400 m. The glacier continues with a low slope to the base of the icefall (I) at 3800 m. Through the icefall the elevation rises above the equilibrium line at 4900 meters (ELA). The thick debris cover insulates the underlying ice slowing the melting. Zhang et al(2010) indicate that thinning and retreat have both accelerated since 1989. The images from Google Earth below are from 2002. The glacier area has been reduced by 0.8 square kilometers over the last 44 years, but more importantly has thinned by 1.1 meters/year in the ablation zone (Pan et al, 2011). In the second image the red arrow indicates the start of the debris cover, and the blue arrow where the river emerges at the terminus. The beginning of the debris cover is noted (DC)(top image), the green arrow indicates where the glacier becomes stagnant and the debris cover is quite thick, the red arrow the terminus, where the glacial river emerges from below the glacier. In the closeup the blue arrows indicate the thick debris covered glacier area and red arrow the terminus where the river emerges. . The retreat rate was 13 meters/year from 1966-1989 and 27 m/year from 1998-2008. They also report a significant reduction in glacier velocity in the ablation zone. This is an indication of increasing stagnation of the terminus area, that will lead to continued downwasting and retreat. The glacier is responding to a temperature warming as noted at the Gongga Alpine Ecosystem Observation and Research Station of the Chinese Ecological Research Network, during 1966–2009, the mean annual temperature at the research station has been increasing by 0.15 to 0.21 C/decade. Two examples of the developing hydropower on the Dadu River fed by the glaciers of Gongga Shan are below with the Dagangshan Hydropower Station, 40 km downstream, top image and Pubugou Hydropower Station, 100 km downstream bottom image.

Urumqihe Glacier, China Separation and Retreat

On March 11, 2010March 11, 2010 By mspeltoIn Glacier Observations2 Comments

Urumqi No. 1 or Urumqihe No.1 Glacier is in the Tian Shan Range of China. The Tain Shan Glaciological Research Station nearby, has led to this being the most closely observed glacier in China over the last 50 years. The glacier’s elevation ranges from 3740 meters to 4500 meters in 2005 the glacier had an area of 1.8 km2 (WGMS, 2010). In 1993 it separated into a larger east branch and a west branch. Since 1988 glaciological measurements are carried out for both branches separately (WGMS, 2010). The first image below is from Nozuma Takeuchi, Chiba University, Japan The second is from the WGMS submitted by Tobias Bolch in 2006.

The dryness and inhospitable nature of the region is evident. What is also evident is the limited snow extent on the glacier in the upper image of the east branch of the glacier. Both glacier branches are seen below, they joined in the foreground outwash plain region just 13 years before this image was taken. This region is one of the most continental areas of the world, dominated by polar and continental air masses from the Arctic and central Asia from autumn through spring, causing very low temperatures and little precipitation. During the summer months monsoonal air masses account for two thirds of the annual precipitation. This makes the Urumqi a summer accumulation type glacier, unusual outside of the Himalayan region, where peak accumulation on the upper part of the glacier and peak ablation on the lower part of the glacier, take part simultaneously in summer.

The regional increase of average air temperature of 0.7 C from 1987 to 2000 in north-western China has led to significant glacial mass losses, including a loss of 12 meters in glacier thickness on Urumqi Glacier in the last 35 years. The Average annual precipitation measured on the glacier is 600 to 700 mm relatively low for a glacier, an indicator of the continental climate. Most glaciers north of the immediate southern boundary with India and Pakistan, in China belong to the continental type and react slower to climate change than glaciers in warmer and wetter environments. The annual temperature at the equilibrium line is -8 to -9 C, the soils around the glacier feature permafrost. Runoff has been observed in the Urumqi River basin and has increased by 30% from 1983-2006. Comparison of runoff from glacier and non-glacier basins indicate a much larger change, change of 150%-200% in glacierized basins over the last 50 years. This is due to enhanced melting of the glacier, providing runoff that had been in long term frozen storage.
The mass balance is assessed at specific points indicated in the first figure below, 45 locations which is a higher than typical density 25 point per km2. The second figure is the contoured result of these measurements in terms of the snow-ice (measured in water equivalent units) gained or lost across the glacier. In this particular year the area of snow cover for both glacier branches is about 33% this is much less than the 65% needed for equilibrium on this glacier leading to a negative balance in 2006-07 of -650 mm (WGMS,2010). The mass loss fits the global pattern and cumulative mean of glaciers reporting to the WGMS. The mass balances losses have continued to increase each decade.