QUANTIFYING GLACIAL-CLIMATE INTERACTIONS AT HINTERISFERNER (AUSTRIAN ALPS) USING WIDELY AVAILABLE GLACIOLOGICAL DATA

Glaciers are important proxies for past and present climate change, especially in a time when most of the world’s glaciers are rapidly retreating. Glaciers respond to climate changes via energy exchanges between the ice surface and the atmosphere, through processes often deemed glacier-climate interactions. By quantifying glacier-climate interactions, we can better predict how glaciers will respond to climate changes, but the data to quantify these interactions are often unavailable. A common metric for glacier health, glacier-wide mass balance, combines both the glacier-climate interactions and the specifics of a glacier’s geometry. We develop a method to isolate the glacier-climate interactions from glacier-wide mass balance records for Hinterisferner (Austrian Alps), a reference glacier within the World Glacier Monitoring Service (WGMS) database. Using WGMS data, we track mass lost and gain at specific elevations on the glacier over a 14-year period. We quantify the mass balance sensitivity to climate changes at specific elevations by linearly regressing mass balanced deviations against climatological data from CRU-TS v4.0 data product.

We find that year-to-year glacier-wide mass balance variability is largely described by temperature with a glacier-wide mass balance sensitivity of 0.43 m/ y of glacier loss per 1°C of warming. The mass balance sensitivity to temperature at specific elevations, which removes the geometric component from the glacier-wide mass-balance, varies from 0.68 to 0.21 m/y of glacier loss per 1°C of warming. The mass balance sensitivity at elevation varies linearly with the greatest magnitude at the lowest elevations. The mass balance sensitivity at specific elevations provides a metric for glacier-climate interactions and illustrates the differing energy exchange processes with elevations. The glacier is most sensitive to temperature changes at the lowest elevations, and the sensitivity is 58% greater than the glacier-wide sensitivity. With continued climate change, portions of the glacier with larger climate sensitivities will move to higher elevations where most of glacier area is located. The future glacier-wide mass balance sensitivity will likely be higher than values realized from current glacier-wide mass balance data.