Glacier reaction to temperature and precipitation change in Central Caucasus, 2001–2010

Abstract

This paper examines changes in surface area and terminus retreat of glaciers in the Greater Caucasus Mountains between 2001 and 2010 using ASTER imagery. The use of consistent high-resolution imagery such as ASTER significantly reduces uncertainties in measurements of glacier shrinkage and retreat and enables assessments at decadal intervals which are important for both scientists and regional decision-makers. Two ASTER images acquired on 15 September 2001 and 29 September 2010 covering central sector of the Greater Caucasus Ridge and the Elbrus glaciated massif were used for glacier mapping. Outlines of 179 glaciers were mapped of which 108 glaciers are located on the northern macroslope of the Greater Caucasus and on Mt Elbrus in the Baksan River catchment (Russia) and 71 are located on the southern macroslope in the Inguri River catchment (Georgia). In total, glaciers lost 5% of their area. Glacier wastage was higher in the Inguri catchment at 5.6%; in the Baksan catchment, glaciers lost 4.3% of their area. Termini positions of 28 valley glaciers were measured on ASTER and aerial photographs to compare rates of glacier retreat in 2001–2010 and 1987–2001.The rate of this recession increased, this fact confirmed by field studies in Baksan basin. Glacier mass balance observations at Garabashi glacier  indicate strong reduction in cumulative mass balance since 1998 providing further evidence on glacier wastage. The observed shrinkage of Caucasus glaciers is mainly connected with increasing in summer temperatures.Increase in precipitation has not compensated for an increase in temperature between 1987–2001 and 2001–2010 periods.