Modern data on glaciation of the northern slope of Tavan-Bogdo-Ola massif (Altai)

As of 2015, 16 glaciers, their total area 23.46 km2 and the weighted-mean altitude of the firn line 3335 m, were isolated on the Northern slope of the of the Tavan-Bogdo-Ola massif (Altai) on the basis of field studies and analysis of satellite images (Landsat-7, SPOT-5, Geoeye-1, CARTOSAT-1). The differences in elevation of the firn lines on the West and East of the investigated area reach 460 m, while the intensity of glaciation differs in 2 times due to changes of annual precipitation from 360 mm in the East to 880 mm in the West. Data on the glaciation had been improved and complemented for three time sections: 1962, 2001, and 2009. Since 1962, areas of the glaciers decreased by 24.3%. The largest rates of the glacial area decreasing took place in 2001–2009. Degradation of the upper parts of the glaciers and uncovered ice-dividing rocks played the major role in the process of retreating. In 2009–2015, the intensity of shortening of the glaciers decreased, and the degradation of their upper parts stopped. In 2000–2009, mainly small glaciers degraded. After 2009, small glaciers have slowed the decline with simultaneous increase of retreating of tongues of the valley glaciers. Abrupt (280 m) shortening of tongue was observed on the glacier Argamdgi-2-Western. This behavior of glacier could be caused by different rate of response to the dramatic warming within the period 1985–2000 and climate stabilization after 2000. If the climatic trends of the last 15 years will be the same in the coming years, we should expect continued rapid retreat of the tongues of the two largest glaciers of this massif along with the further slowdown of the retreat of small glaciers.