Using surface velocities to calculate ice thickness and bed topography: A case study at Columbia Glacier, Alaska, USA

R.W. McNabb; R. Hock; Shad O'Neel; Lowell A. Rasmussen; Y. Ahn; M. Braun; H. Conway; S. Herreid; I. Joughin; W.T. Pfeffer; B.E. Smith; M. Truffer

doi:10.3189/2012JoG11J249

Using surface velocities to calculate ice thickness and bed topography: A case study at Columbia Glacier, Alaska, USA

Journal of Glaciology

By: R.W. McNabb, R. Hock, Shad O'Neel, Lowell A. Rasmussen, Y. Ahn, M. Braun, H. Conway, S. Herreid, I. Joughin, W.T. Pfeffer, B.E. Smith, and M. Truffer

https://doi.org/10.3189/2012JoG11J249

Links

More information: Publisher Index Page (via DOI)
Document: Report
Open Access Version: Publisher Index Page
Download citation as: RIS | Dublin Core

Abstract

Information about glacier volume and ice thickness distribution is essential for many glaciological applications, but direct measurements of ice thickness can be difficult and costly. We present a new method that calculates ice thickness via an estimate of ice flux. We solve the familiar continuity equation between adjacent flowlines, which decreases the computational time required compared to a solution on the whole grid. We test the method on Columbia Glacier, a large tidewater glacier in Alaska, USA, and compare calculated and measured ice thicknesses, with favorable results. This shows the potential of this method for estimating ice thickness distribution of glaciers for which only surface data are available. We find that both the mean thickness and volume of Columbia Glacier were approximately halved over the period 1957–2007, from 281m to 143 m, and from 294 km³ to 134 km³, respectively. Using bedrock slope and considering how waves of thickness change propagate through the glacier, we conduct a brief analysis of the instability of Columbia Glacier, which leads us to conclude that the rapid portion of the retreat may be nearing an end.

Study Area

Additional publication details
Publication type	Article
Publication Subtype	Journal Article
Title	Using surface velocities to calculate ice thickness and bed topography: A case study at Columbia Glacier, Alaska, USA
Series title	Journal of Glaciology
DOI	10.3189/2012JoG11J249
Volume	58
Issue	212
Year Published	2012
Language	English
Publisher	International Glaciological Society
Publisher location	Cambridge, UK
Contributing office(s)	Alaska Science Center
Description	14 p.
Larger Work Type	Article
Larger Work Subtype	Journal Article
Larger Work Title	Journal of Glaciology
First page	1151
Last page	1164
Country	United States
State	Alaska
Other Geospatial	Columbia Glacier
Google Analytic Metrics	Metrics page