Glaciers and Climate Project

Mass Balance Summary

Benchmark Glaciers

The USGS Benchmark Glacier Project measures changes in mass balance at five benchmark glaciers: Gulkana (AK), Wolverine (AK), Lemon Creek (AK), South Cascade (WA), and Sperry (MT). The graphics below depict the mass balance over the period of record for each glacier. The Alaskan and Washington datasets constitute the longest continuous set of mass balance data in North America (O’Neel and others, 2019). With the inclusion of Sperry Glacier in 2013, these five research sites were unified into a single project with common field and analysis methodologies to enable comparison among the glaciers. This project aims to advance the quantitative understanding of glacier-climate interactions from local to regional scales. The current focus is on merging the long-term field records with newer, richer remote sensing data.

Source: O'Neel, S., McNeil, C., Sass, L., Florentine, C., Baker, E., Peitzsch, E., McGrath, D., Fountain, A., and Fagre, D. (2019). Reanalysis of the US Geological Survey Benchmark Glaciers: Long-term insight into climate forcing of glacier mass balance. Journal of Glaciology, 65(253), 850-866. https://pubs.er.usgs.gov/publication/70207167

Each year these glaciers go through a seasonal cycle, gaining mass in the winter and losing mass in the summer, which combine as the annual change in mass. The gray bars represent the winter accumulation, the black bars represent summer ablation, and the colored bars represent the annual mass balance, expressed in meters of water equivalent.
The cumulative mass change at each glacier, expressed in meters of water equivalent. Note that each glacier is measured relative to the start of mass balance measurements at that site. Geodetic mass balances (black squares) from photogrammetrically derived digital elevation models are used to constrain the time-series.