Glacier mass balance

Abstract

Glacier mass balance as the difference between mass gain through snow accumulation and mass loss through melting and sometimes calving is a rather direct result of fluctuating atmospheric conditions and a key natural indicator of global climate change. International monitoring strategies combine in situ observations at networks of stakes and snow pits (direct glaciological method for process understanding and annual to seasonal time resolution) with repeated mapping (geodetic/photogrammetric method for calibration of field measurements and determination of overall volume/mass change). Modern remote sensing techniques include laser altimetry, radar, gravimetry, and differencing of digital elevation models (DEM) for large glacier ensembles. Long-term in situ mass balance measurements for entire glaciers started after World War II, today involve regular observations at about 100 glaciers worldwide, and reveal a trend of rapidly accelerating mass loss during the past decades.