Climate variability and glacier reaction in the Austrian castern Alps

Abstract

A carefully homogenized climate dataset is used to interpret glacier behaviour in the Austrian Alps. Periods of glacier advance are generally more maritime and cooler, with reduced sunshine duration and increased precipitation sum during the ablation period. Periods of retreat are associated with a more continental, warmer climate, with increased sunshine duration and reduced precipitation sum. Three recent sub-periods of Austrian glacier behaviour are documented by direct measurement of glacier mass balance (before 1965 more negative; 1965-81 more positive; since 1982 more negative). A long-term mass-balance series in the eastern part of the Austrian Alps parameterized by snow-depth measurements indicates very clearly that periods of more negative mass balance have a higher correlation to summer air temperature and a lower correlation to winter accumulation. Periods of more positive mass balance are highly correlated to winter accumulation and only slightly correlated to summer temperature. The positive mass-balance period 1965-81 is also characterized by negative North Atlantic Oscillation index values which caused an increased meridional circulation mode, resulting in a north-westerly to northerly precipitation regime during winter.