June 4, 2019
Daishapu Glacier (D) and Ruorangqubu Glacier (R) in 1993 and 2018 Landsat images. The yellow arrows indicate the 2018 terminus location of both glaciers and the purple dots the snowline. Notice the lake expansion at the terminus of both glaciers. Locations 1-4 are tributaries.
Daishapu Glacier and Ruorangqubu Glacier are in the eastern Himalaya located just north of the Himalayan divide and draining north into the Yarlung Zangbo. This is a remote area with little development downstream for 100+ km. Li et al (2010) examined glacier change over the last several decades in China and found ubiquitous glacier retreat and commonly lake formation as glaciers retreated.
In 1993 Daishapu Glacier has a debris covered terminus ending in a 1 km long proglacial lake at 5000 m. Tributaries 1-4 all reach the main Daishapu trunk. The snowline in 1993 is at 5600 m in December. Rurorangqubu Glacier had a low slope debris covered terminus without a proglacial lake at 5300 m. A tributary from the east joins the glacier 1 km above the terminus. By 2001 Daishapu has retreated several hundred meters, while tributaries 1-4 all still connect. The snowline is at 5800 m in December. Rurorangqubu still has no proglacial lake. In 2015 both glaciers have proglacial lakes at the terminus. Tributary #2 no longer reaches the main Daishapu. The eastern tributary no longer reaches the main trunk of Rurorangqubu Glacier. In 2018 the proglacial lake at the end of the Daishapu Glacier is 1800 m long, with a retreat of 700-800 m since 1993. Tributary #4 has now begun to detach. Rurorangqubu Glacier has a 600 m long proglacial that has formed which represents the retreat of the glacier since 1993. The snowline in 2018 is at 6000 m in December. The high snowline persisting into December is a trend in the area that is not positive for glacier mass balance, this has been observed around Mount Everest and on the China-Bhutan border. These two glaciers at the crest of the Eastern Himalaya are both retreating, have expanding proglacial lakes and separating tributaries. This is a common story in the region as seen at Thong Wuk Glacier and Jiongla Glacier.
Daishapu Glacier (D) and Ruorangqubu Glacier (R) in 2001 and 2015 Landsat images. The yellow arrows indicate the 2018 terminus location of both glaciers and the purple dots the snowline. Notice the lake expansion at the terminus of both glaciers. Locations 1-4 are tributaries.