Relationship between recent climate change, ablation conditions of glaciers of the East Sayan Range, Southeastern Siberia, and atmospheric circulation patterns

The 2001-2013 sum of positive temperatures (SPT) record, as a proxy of snow/ice ablation, has been obtained for the high-mountain glaciarized Munku-Sardyk massif, East Sayan Mountains, using daily NCEP/NCAR reanalysis data. The SPT (and ice melt) demonstrates a significant decreasing trend, with the highest values in 2001, 2002, and 2007, and the lowest in 2013. We have investigated relationships between potential summer ablation and synoptic-scale conditions over the study area. Increased summer ablation is associated with anticyclonic pressure field, secondary anticyclones with cloudless weather conditions, and low gradient field. Reduced ablation is strongly correlated with Arctic air invasions, cyclonic pressure field, and southern cyclones entailed the advection of cold air masses. Statistically significant correlations have been found between the SPT data and meridional circulation intensity and cyclonic/anticyclonic activity. Variability of regional atmospheric circulation conditions in the early 21st century resulted in change of high-mountain snow/ice melt regime and could lead to future change of the East Sayan glaciers.