Title Surface mass balance, thinning and iceberg production, Columbia Glacier, Alaska, 1948-2007
Author Rasmussen, L.A.; Conway, H.; Krimmel, R.M.; Hock, R.
Author Affil Rasmussen, L.A., University of Washington, Department of Earth and Space Sciences, Seattle, WA. Other: University of Alaska Fairbanks; Uppsala University, Sweden
Source Journal of Glaciology, 57(203), p.431- 440, . Publisher: International Glaciological Society, Cambridge, United Kingdom. ISSN: 0022-1430
Publication Date 2011
Notes In English. NSF Grant ARC-0732739. 47 refs. GeoRef Acc. No: 310273
Index Terms ablation; precipitation (meteorology); calving; glacial geology; glaciers; glacier ablation; ice; ice cover; icebergs; mass balance; meteorology; models; snow; weather observations; United States--Alaska-- Anchorage Quadrangle; United States--Alaska-- Columbia Glacier; United States--Alaska-- Valdez Quadrangle; Alaska; Anchorage Quadrangle; atmospheric precipitation; Columbia Glacier; United States; Valdez Quadrangle
Abstract A mass-balance model using upper-air meteorological data for input was calibrated with surface mass balance measured mainly during 1977-78 at 67 sites on Columbia Glacier, Alaska, between 135 and 2645 m a.s.l. Root-mean-square error, model vs measured, is 1.0 m w.e.a -1, with r2 = 0.88. A remarkable result of the analysis was that both precipitation and the factor in the positive degree-day model used to estimate surface ablation were constant with altitude. The model was applied to reconstruct glacier- wide components of surface mass balance over 1948-2007. Surface ablation, 4 km3 ice eq.a-1 (ice equivalent), has changed little throughout the period. From 1948 until about 1981, when drastic retreat began, the surface mass balance was positive but changes in glacier geometry were small, so the positive balance was offset by calving, approx. 0.9 km3 ice eq.a-1. During retreat, volume loss of the glacier accounted for 92% of the iceberg production. Calving increased to approx. 4.3 km3 ice eq.a-1 from 1982 to 1995, and after that until 2007 to approx. 8.0 km3 ice eq.a-1, which was about twice the loss by surface ablation, whereas prior to retreat it was only about a quarter as much. Calving is calculated as the difference between glacier- wide surface mass balance and geodetically determined volume change.
URL http://hdl.handle.net/10.3189/002214311796905532
Publication Type journal article
Record ID 65007287