Contributions to Jarvis Creek Watershed, Alaska, from Winter Accumulation and Glacier Melt Inferred Through Airborne and Ground-Penetrating Radar
Abstract
Glacier meltwater contributions to river discharge has been increasing in much of the Arctic, likely because of higher air temperatures. For small glaciers that provide a large portion of meltwater to downstream discharge, a sustained negative mass balance is concerning to surrounding ecosystems because the water budget will ultimately decline when glacier ice disappears. Separating components of the hydrological budget is important for predicting future discharge, particularly when major inputs such as glacier ice melt are at risk of total loss. Jarvis Glacier in Eastern Alaska offers an example of this potential scenario. It is a 6-km long glacier that has been in retreat since the 1950's, yet it accounts for 15% of the annual downstream discharge into Jarvis Creek (Liljedahl et al., 2017). In March 2012 through April 2017 we completed yearly airborne and ground-penetrating radar surveys over Jarvis Glacier and its surrounding non-glaciated watershed. These surveys were conducted to assess winter snow accumulation and its potential contribution to the hydrological budget of Jarvis Creek. We also surveyed glacier ice thicknesses to estimate ice volume and potential long term future meltwater contributions to Jarvis Creek based on its sustained negative mass balance. High-frequency radar collected across Jarvis Glacier reveal winter accumulation rates between 1.1-1.9 m SWE. Thickness of winter snow in the surrounding glacier-free valleys is highly variable but it tended to accumulate as drifts near ridge tops or low in the valleys. Low-frequency GPR reveals ice thickness reaching 250 m, mid-glacier, tapering to less than 100 m near the debris-rich terminus. Several over-deepened basins exist and an obvious polythermal structure with 20-30 m of cold ice overlaying temperate ice is also evident. Our presentation will summarize further details of these results in relation to current and potential future contributions of glacier ice and winter snowpack melt to Jarvis Creek watershed.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.C33A1173C
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0762 Mass balance 0764 Energy balance;
- CRYOSPHERE;
- 1621 Cryospheric change;
- GLOBAL CHANGE;
- 1827 Glaciology;
- HYDROLOGY