May 5, 2019
Zaroshkul Glacier Retreat, Tajikistan
Posted by Mauri Pelto
Zaroshkul Glacier in 1994 and 2018 Landsat imagery. Z=Zaroshkul Lake, A=Developing lake, red arrow=1994 terminus, yellow arrow=2018 terminus and purple dots=snowline.
Zaroshkul Lake is in the midst of the Pamir Range, Tajikistan and is surrounded by glacier clad mountains. Here we examine Landsat imagery from 1994-2018 of the Zaroshkul Glacier the largest glacier in the basin to identify changes. The Pamir Range has experienced less glacier mass loss than most other regions of High Mountain Asia, -0.08 m/year from 2000-2016 (Brun, et al. 2017). This is supported by the sustained but modes volume loss on Fedchenko Glacier, the largest glacier in the region Lambrecht et al (2014).
In 1994 Zaroshkul Glacier terminated in a 500 m long proglacial lake and the snowline is at 4900 m in late summer. The accumulation area ratio (AAR) is ~40%, indicating a significant negative mass balance, needs to be close to 60% to be in equilibrium. In 2000 and 2001 the proglacial lake has expanded to a length of 700 m and the snowline in both years is ~4900 m, again too high to sustain the glacier size. In 2015 the snowline is just above 5000 m and less than 25 % of the glacier is in the accumulation zone.By 2018 Zaroshkul Glacier has retreated 600 m and the proglacial lake is now 700 m wide. The lake is impounded by a wide and by all appearances stable moraine. The snowline on 8-18-2018 is at 5000 m with an AAR of less than 30% indicating continued mass loss, that will generate ongoing retreat. Three valleys to the north of Zaroshkul Glacier at Point A glacier retreat from 1994 to 2018 has revealed formation of a new small proglacial lake.
The significant continued mass loss of Zaroshkul Glacier fits the pattern of larger volume and area losses on smaller Pamir glaciers as reported by Khromova et al, (2006)
Zaroshkul Glacier in 2000, 2001 and 2015 Landsat imagery. Z=Zaroshkul Lake, A=Developing lake, red arrow=1994 terminus, yellow arrow=2018 terminus, and purple dots=snowline.