Surface albedo as a proxy for the mass balance of Greenland's terrestrial ice

Satellite observations are critical to understanding the mass balance of Greenland’s terrestrial ice (Fig. 1). The Gravity Recovery and Climate Experiment (GRACE) satellite constellation provides monthly gravimetry observations that can directly assess mass balance. Temporal data gaps have begun to appear in the GRACE record due to declining satellite function. In anticipation of further deterioration in the coverage of GRACE, we have explored an empirical relation between ice-surface albedo (or reflectance) and ice-mass balance to fill the gaps in the gravimetry record of Greenland’s ice-mass balance. As surface albedo observed by the moderate-resolution imaging spectroradiometer (MODIS) aboard the Terra satellite is available in near real-time, employing a MODIS-derived proxy permits near real-time estimates of Greenland ice-mass balance. The Geological Survey of Denmark and Greenland has begun employing the albedo – mass-balance relation described here to issue near real-time estimates of Greenland ice-mass balance during the summer melt season at www.polarportal.org.