Surficial glaciology of Jakobshavns Isbræ, West Greenland: Part I. Surface morphology

作者：Keith A. Echelmeyer, Ted S. Clarke, William D. Harrison · 发表于：Journal of Glaciology · 年份：1991 · DOI：10.3189/s0022143000005803 · 被引用次数：55 · 研究领域：Cryospheric studies and observations、Winter Sports Injuries and Performance、Climate change and permafrost

Abstract Jakobshavns Isbræ is a large, fast-moving ice stream/outlet glacier in West Greenland which ends at a floating, calving front. It drains about 6.5% of the area of the Greenland ice sheet. Studies of its surface morphology are described in this paper. The surface is relatively steep (0.01–0.03) and the thickness is large (up to 2600 m along the center line (Clarke and Echelmeyer, 1989)), indicating very high driving stresses (200–300 kPa). The ice stream is about 6 km wide and 85–90 km long, all of which is in an area of surface melting. The base of the ice stream, and of much of the drainage area, is below sea level. Marginal crevasse zones have a width on the order of the width of the ice stream itself. Unique surficial features are ice blisters and lakes; the latter have a sequence of ogive-like features on their floating ice cover which can be used to determine velocity. There is a pinning point near the terminus which may act as a stabilizing influence, possibly playing a role in halting, at least temporarily, a recent retreat of the terminus. Ice-thickness estimates at the terminus lead to a flux which is less than previously assumed by others (e.g. Bindschadler, 1984; Pelto and others, 1989) when estimating Jakobshavns Isbræ’s drainage basin to be nearly in balance. The driving stresses on Jakobshavns Isbræ are an order of magnitude higher than those of the ice streams of West Antarctica. Its crevasse patterns are much less localized. Its relatively unconfined ...