Recent glacierization of the Tsambagarav ridge (North‑Western Mongolia) and its changes since the Little Ice Age maximum

Abstract

Characteristics of glacierization of the Tsambagarav mountain ridge were determined on the basis of images obtained from satellites Corona, Landsat‑5, Spot‑4, Landsat‑8 together with results of field investigations. Inventories of glaciers located on the ridge had been prepared for three time periods: 1968, 2006, and 2015. Glacierization of the ridge during the Little Ice Age (LIA) maximum was then reconstructed. In 2015, 67 glaciers formed the ridge glacierization with their total area 68.41 km2. Mean weighed altitude of the firn line averaged 3748 m. The flat‑top glaciers accounted for almost 40% of the glacierization area, and the glaciers composed 6 complexes. For the period of the LIA maximum, 73 glaciers had been reconstructed, their total area was 128.4 km2, and the calculated firn line altitude – 3583 м; these glaciers were combined into two complexes where the flat‑top glaciers predominated as well. By 1968, the area of the glacierization decreased by 36%, and the firn line altitude increased by 89 m. By 2006, area of glaciers decreased down to 71.32 km2, and the firn line altitude increased more by 60 m. Finally, in 2006–2015, area of the glacierization contracted additionally by 2.91 km2, and the firn line altitude still more increased by 16 m. Over the whole period from the LIA maximum, the flat‑top glaciers reduced the most. The general rate of contraction of glaciers tends to increase. Reconstructed rates of retreating of the valley glaciers of the Tsambagarav ridge are similar to estimates of other researchers made for the nearest centers of glacierization. Continuation of the current trend to a rise of summer temperature and a growth of precipitation should result in primary fast degradation of the flat‑top glaciers and reorganization of morphological structure of the glacierization.

Present Glaciers of Tavan Bogd Massif in the Altai Mountains, Central Asia, and Their Changes since the Little Ice Age

“…Comparison with the relative area of the valley glaciers of the nearest glacial centers (Ikh-Turgen ~50%[69], Mongun-Taiga ~50%[70], Turgeni-Nuru ~55%[71], Kharkhiraa 58%[71]) reveals the high grade of this type of glacier for Tavan Bogd. Attention is drawn to the small number and area proportion of flat summit glaciers (1-2%), which is not typical for the Mongolian Altai and the southeast of the Russian Altai; for example in the total area of Tsambagarav ridge, flat summit glaciers comprise about 40%[72].…”

The Components of the Glacial Runoff of the Tsambagarav Massif from Stable Water Isotope Data

“…The complex cirques are developed on the northeastern slope, and from the west to the east, the depth of dissection of the relief increases. As a result, there are large valley and cirque-valley glaciers on the northeastern slope; the tongues of the largest of them descend to an altitude of 3000 m. The ELA on the glaciers of this complex lies within the range of 3500-3750 m [15]. In Reference [16], the authors stated a less intense retreat and thinning of the Tsambagarav glaciers compared to the Potanin glacier (the largest one in the Altai).…”

“…A recent report [15] showed that there were 67 glaciers in Tsambagarav, with a total area of 68.41 km 2 , and the weighted average equilibrium line of altitude (ELA) was about 3750 m [15]. The main glaciers of the Tsambagarav Range are grouped into seven glacier complexes.…”

“…According to the data received at the Bayannur station, the average summer temperature is 16.5 • C, and the average annual precipitation rate is 87 mm (1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004). At Erdenburen station, these values are 16.6 • C and 78 mm, respectively [15]. The precipitation at the level of the firn boundary was estimated to be 270 mm [17].…”

“…This is the largest glacier of the massif, which produces more meltwater than the others. The average thickness of the glacier tongue is 132 meters [15].…”