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

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.