As a direct measure of glacier mass balance, the ELA facilitates explicit comparisons of climate in space and time by accounting for dependencies on glacier size, extent, and shape, and by integrating the myriad variables that can drive changes in climate into a single comparable metric. The ELA is the boundary between the accumulation and ablation zones on a glacier and represents the elevation at which the annual amount of mass added through accumulation exactly equals the annual amount of mass lost through ablation.

A more comparable measure of the glacier response to climate change than glacier area or length changes is the concept of the equilibrium line altitude (ELA). Such transitions can be visually drastic, with some glaciers changing by kilometers in response to minor perturbations in climate. An annual mass surplus (when net accumulation exceeds ablation) leads to glacier growth, while a deficit leads to glacier retreat. As a test of the model’s efficacy, we compare the model results for present-day glaciers in the Swiss Alps with previously published estimates of equilibrium line altitudes and intermediate model outputs.Ĭhanges in glacier size and extent are fundamentally related to the mass balance of the glacier. We provide custom MATLAB functions as a user-friendly and generally-applicable method to estimate glacier equilibrium line altitudes from only a limited number of glacier bed topography and glacier width measurements. Here we detail a physical steady-state model for alpine glaciers relating directly to glacier mass balance (via the equilibrium line altitude) while retaining the simplicity of other morphology methods, and simultaneously including error estimates. Many glacier models fall into one of two endmembers: either highly complex transient models requiring careful tuning of multiple parameters to individual glaciers, or basic empirical correlations of glacier area and length with few considerations for local and regional variations in characteristics. Advancements to understand and model glacial changes and the variables influencing them are therefore paramount. They also represent critical water resources for areas around the globe, with the potential for far-reaching effects in a warming world.

Alpine glaciers, with their valuable combination of highly sensitive response to climate and near-global extent, are powerful tools for investigating previous and present climate changes.

Subplot ela