Correspondence Among Mid-Latitude Glacier Equilibrium Line Altitudes, Atmospheric Temperatures, and Westerly Wind Fields

Abstract

Mountain glaciers are highly sensitive to climate change. However, the extent to which glaciers capture regional to hemisphere-scale atmospheric processes remains uncertain, hindering paleoclimatic interpretations derived from moraine-based glacier reconstructions. Here, we evaluate how mid-latitude glacier systems monitor climate by comparing climate reanalysis products with glacier annual equilibrium line altitude (ELA) elevations from the antipodal Southern Alps of New Zealand and European Alps. We find significant regional and hemispheric correlations between glacier annual ELA and summer tropospheric temperatures. Annual ELA also exhibit positive correlations with the latitude of the westerly jets in both hemispheres. These results indicate that westerly wind-belt latitude modulates the proportion of cold versus warm air masses influencing these glacier systems. These results highlight the sensitivity of mid-latitude glaciers to atmospheric temperatures and circulation, with implications for interpreting moraine-based paleoclimate reconstructions. Combined impacts of ongoing tropospheric warming and poleward-shifting westerlies will likely accelerate recession of mid-latitude glaciers. © 2022. The Authors.