Climatic controls on the equilibrium-line altitudes of Scandinavian cirque glaciers

Abstract

The equilibrium-line altitudes (ELAs) of reconstructed palaeoglaciers have been widely used to assess palaeoclimatic conditions, yet this concept has rarely been tested using modern glaciers. To address this shortcoming, correlations between the ELAs of 513 modern cirque glaciers and present-day climatic and topographic variables across Scandinavia, as well as regional trends in ELA and climate, are analysed. ELAs are calculated using the Area-Altitude-Balance-Ratio method, with a ratio of 1.5 ± 0.4. Results indicate that glacier ELAs are strongly correlated with distance from the coast. This reflects the present-day precipitation pattern of the region (characterised by high precipitation near the sea) and demonstrates a climate dominated by a maritime-continental transition. Temperature explains differences in glacier ELA regional trends as well as ELA changes with latitude. Following standard meteorological convention, Scandinavia is divided into two macro-climate regions and analyses are run within the macro-regions as well as the complete dataset. The strength of correlations between ELA and precipitation increases when the study is divided into northern and southern macro-regions. These results test long held assumptions about relationships between climate and cirque glacier ELA, which is of particular relevance to palaeoclimatic studies based on the reconstruction of former cirque glaciers.