June 7, 2016

Bailang Glacier and Angge Glacier Retreat, China 1995-2015

Posted by Mauri Pelto

bailang compare

Comparison of 1995 and 2015 Landsat image illustrating 1995 (red arrows) and 2015 terminus locations (yellow arrows) of Bailang Glacier (B) and Angge Glacier (A).  Purple arrows indicate areas upglacier of expanding bedrock due to glacier thinning. Head of Chubda Glacier (C), Bhutan indicated. 

Bailang Glacier and Angge Glacier, China are adjacent to the Chubda Glacier, Bhutan.  Despite being in a different nation on a different side of the Himalaya, the behavior is the same. These are both summer accumulation type glaciers that end in proglacial lakes.  Both lakes are impounded by broad moraines that show no sign of instability for a potential glacier lake outburst flood. The number of glacier lakes in the adjacent Pumqu Basin to the west has increased from 199 to 254 since the 1970’s with less than 10% deemed dangerous  (Che et al, 2014) Here we compare Landsat images from 1995 and 2015 to identify their response to climate change.   The second Chinese Glacier inventory (Wei et al. 2014) indicated a 21% loss in glacier area in this region from 1970 to 2009.

Bailang Glacier in 1995 terminated in a proglacial lake that was 2.1 km long at an elevation of ~5170 m, red arrow. Angge Glacier terminated in a lake that was 1 km long at an elevation of ~5020 m.  By 2001 both glaciers had experienced minor retreat of less than 250 m.  By 2014 both lakes had expanded considerably due to retreat, no significant change in water level had occurred. By 2015 Bailang Glacier had retreated 900-1000 m and the lake was now 3 km long.  A key tributary on the west side near the yellow arrow had also detached. There is no significant slope change in the lower 1 km of the glacier indicating retreat should continue enhanced by melting in and calving in the proglacial lake.  For Angge Glacier retreat from 1995 to 2015 was 800 to 900 m, with the glacier retreating to a westward bend in the lake basin.  The glacier has an icefall just above the current terminus suggesting the lake basin will soon end, which should slow retreat. The pattern of retreat and lake expansion is quite common as is evidence by Gelhaipuco, Thong Wuk and Longbashaba Glacier.

bailang glacier 2001

2001 Landsat image illustrating 1995 (red arrows) and 2015 terminus locations (yellow arrows) of Bailang Glacier (B) and Angge Glacier (A).  Head of Chubda Glacier (C), Bhutan indicated. 

bailang glacier 2014

2014 Landsat image illustrating 1995 (red arrows) and 2015 terminus locations (yellow arrows) of Bailang Glacier (B) and Angge Glacier (A).  Head of Chubda Glacier (C), Bhutan indicated.