An Open-Source Tool for Mapping Key Metrics of Glacier Health from Space

Kara Ann Lamantia, Laura Larocca, Rainey Aberle, Fabien Maussion, James M Lea

Satellite-based observations enable monitoring of glacier health metrics, essential for assessing glacier response to climate change and the environmental services they provide. Here, we present an open-source tool for automated mapping of key climate- and mass balance- modulated parameters, including total visible ice area, snow-covered area, accumulation-area ratio, and snowline altitude. The tool uses Landsat near-infrared reflectance, commonly used spectral band ratios, and scene-specific thresholding to distinguish snow-cover from ice or firn surfaces. Validation across 59 glaciers spanning 13 regions shows strong agreement with manual interpretation of satellite imagery and weak agreement with field observations from the World Glacier Monitoring Service (WGMS) likely reflecting differences in methodology, observation timing, and the transient nature of glacier surface conditions. While the tool increases the availability of glacier observations beyond those provided by WGMS, these metrics should be interpreted as complementary transient observations rather than direct substitutes for end-of-season or field-based measurements. Beyond the glaciers studied here, the tool is designed to enable accessible generation of multi-decadal glacier health time series for individual glaciers with appropriate user evaluation and consideration of known limitations. Thus, the tool will hold value for a range of users, particularly for education, outreach, and community stakeholders.