Accumulation rates in Northwest Greenland from continuous GPR profiling along the Greenland Inland Traverse
Abstract
Snow accumulation is one of the fundamental parameters governing the mass balance of the Greenland Ice Sheet. While many point measurements of accumulation exist from shallow and deep ice cores, there are few spatially extensive and continuous records of accumulation in Greenland, particularly in the northwest quadrant. In April and May 2011, the Greenland Inland Traverse traveled via tractor train from Thule Air Base in northwest Greenland to Summit Station, at the center of the ice sheet. The science team on the traverse collected both point and profile measurements along the route. Kinematic GPS and 400 MHz GPR profiles provide geolocated subsurface stratigraphy. Density measurements from snowpits and shallow cores on the profile allow us to determine the true depth of radar reflecting horizons, commonly interpreted to be isochrons. We use three ice cores collected at the beginning, the end, and roughly the middle of the route to date horizons. We traced strong reflecting horizons along the entire route. From the combination of dated, traced horizons, density measurements, and position measurements, we determine accumulation rates continuously along the traverse route. We find our traverse route begins in a high-accumulation area, and accumulation decreases as we cross to the east side of the summit ridge. Accumulation then climbs again as we approach summit (directly on the summit ridge). We compare our accumulation rates with previous studies, both measurements (traverse and point measurements) and models.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.C13G..08H
- Keywords:
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- 0726 CRYOSPHERE / Ice sheets;
- 0736 CRYOSPHERE / Snow;
- 0762 CRYOSPHERE / Mass balance;
- 0776 CRYOSPHERE / Glaciology