Wet firn processes and the implications for geodetic mass balances
Abstract
The increasing quantity and quality of surface elevation observations presents an unprecedented opportunity to quantify glacier/ice-sheet mass balance at finer spatio-temporal resolution than ever before, but all analyses hinge on material property assumptions required to convert surface elevation change to mass change. Limiting the analysis to multi-year time intervals can decrease the uncertainties caused by changes in the density structure, but the errors from these assumptions are unquantified and could still be quite large. Moreover, the limited calculations of material density that have been used are derived from models developed for cold, dry polar snow, even though wet, temperate snow and firn characterizes most mountain glaciers. To address these issues, we present a time series of 25 m long firn cores collected at a single site throughout the summer melt season on Wolverine Glacier, Alaska. The physical measurements of the cores are complemented by continuous time series of surface air temperature, surface lowering, and radar-derived snow stratigraphy. The point measurements are extended with an extensive stake network, airborne snow radar, and seasonal digital elevation model construction. Initial results show complicated firn stratigraphy and water penetration throughout the entire core length. Understanding wet-firn processes is an essential step to improving the accuracy of geodetic mass balances, especially over short time scales, which will improve the calibration of field and remote sensing efforts to understand ongoing and future mass balance.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.C41C0684S
- Keywords:
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- 0720 Glaciers;
- CRYOSPHEREDE: 0738 Ice;
- CRYOSPHEREDE: 0758 Remote sensing;
- CRYOSPHEREDE: 0762 Mass balance 0764 Energy balance;
- CRYOSPHERE