The Altai Mountains extend more than 2000 km through Central Asia (Fig. 1). Traditionally, these mountains have been subdivided into the Russian, Mongolian, and Gobi Altai. The Russian Altai Mountains are located in the border region of Russia, Mongolia, China, and Kazakhstan between approximately 48 and 52°N latitude and 83 and 91°E longitude. The highest peak is Mt. Belukha (4506 m ASL). Our study focused in and around the South Chuyskiy Range (49°40'-50°N, 87°30'-88°30'E), which is one of the highest ranges in the region.
The South Chuyskiy Range encompasses three large U-shaped valleys (Taldura, Akkol, and Karaoyuk) which were occupied by ice at various times in the Holocene (e.g., Okishev, 1982). Radiocarbon dates from the Akkol valley give ages for the moraines of the Sofiyskiy glacier ranging 5700-250 years BP (Okishev, 1982).
Three Russian meteorological stations are located in and around the study area (Fig. 9). The Kosh-Agach station (1757 m ASL) is at the centre of the Chuyskiy basin, the Aktru station (2121 m ASL) is in a mountainous district of the North Chuyskiy Range, and the Onguday meteorological station (832 m ASL) is located 150 km northwest of the study area. The MAAT at these stations exhibited significant warming trends for 1965-2000 (Fig. 10). Average MAATs at the Onguday and Kosh-Agach stations for 1966-1975, for example, were -0.4 and -5.3°C, respectively, while those for 1985-1994 were 0.6 and -4.2°C, respectively.
Annual precipitation for 1972-1995 at the Onguday station was approximately 360 mm and recorded winter precipitation (December to February) was only 22 mm. The minimal winter precipitation results in a characteristically shallow winter snow pack.
Figure. 10 MAATs at the Onguday (832 m ASL), Kosh-Agach (1757 m ASL) and Aktru (2121 m ASL) stations for 1965-2000 (modified Fukui et al., 2007b).
Permafrost-indicator features (rock glaciers, pingos, and ice-wedge polygons) occur at many places in and around the South Chuyskiy Range of the Russian Altai Mountains (Fig. 11). Based on the distribution of these features and the results of two years of air temperature monitoring, Fukui et al. (2007b) determined that the sporadic/patchy permafrost zones extend from 1800-2000 m ASL and the widespread discontinuous/continuous permafrost zones are above 2000 m ASL.
Glaciers in the Altai are of the summer-accumulation-type (Fujita et al., 2004; Pattyn et al., 2004; Smedt and Pattyn, 2004). The equilibrium line altitude (ELA) lies between 2500 and 2900 m ASL on north-facing slopes and from 2700 to 3100 m ASL on the south-facing slopes (Ostanin and Mikhailov, 2005). Steppes cover a large part of the study area. Larch forests extend up the mountains, with the timberline lying at approximately 2500 m ASL on north-facing slopes (Nakazawa et al., 2004).
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