November 14, 2022
Daoge and Jiangpu Glacier retreat and proglacial lake expansion in Landsat images from 1988 and 2022. Yellow arrow is the 2022 terminus location, red arrow the 1988 terminus location and purple dots the snowline.
The Jiangpu Glacier and Daoge Glacier are the second and third largest glaciers in the Nyainqentanglha East Range. They flow south in adjacent valleys that feed the Yi’ong Tsangpo, which joins the Parlung Zangbo. Draining north from the same mountains is Jiongla Glacier, which retreated 3200 m from 1988-2015. Qin ji et al (2018) noted glacier recession of 1.24% per year from 1999-2015 in this range, in response to rising annual air temperature. Here we examine satellite imagery from 1988, 2000, 2015 and 2022 to identify the changes in these glaciers.
In 1988 Daoge Glacier terminates in a proglacial lake at ~4000 m that is 1.3 km long. Jiangpu Glacier terminates at a moraine complex at ~3250 m. The snowline in 1988 is at 4600-4700 m. By 2000 there is limited retreat evident at both glaciers and the snowline is at 4500-4600 m. In 2015 the lake at the terminus of Daoge has expanded to 2.5 km, while there is still no lake at the terminus of Jiangpu, with the snowline at 4800 m. In 2022 the summer heat wave experienced by the region pushed the snowline up to 5100-5200 m on Aug. 11, 2022. The lake at the terminus of Daoge Glacier has expanded to 3.2 km in length. For Jiangpu Glaicer a 0.4 km² lake has formed at the terminus due to a landslide triggered by an earthquake swarm in 2020 (Sheth, 2020). Glacier retreat from 1988-2022 has been 1900 m at Daoge Glacier and 2050 m at Jiangpu Glacier.
The high snowline in recent years will continue the retreat of both glaciers, which both have stagnant terminus regions for ~3 km above the current terminus location. There is no slope change at Daoge Glacier indicating lake expansion is near and end. At Jiangpu Glacier the lake is not expanding upvalley, and appears likely to fill in with sediment. This is not surprising given this is not a erosional basin, but a shallow valley fill lake impounded by landslide sediments.
Daoge and Jiangpu Glacier retreat and proglacial lake expansion in Landsat images from 2000 and 2015. Red arrows the 1988 terminus location and purple dots the snowline.