DOI: 10.1029/2017JF004541
Scopus记录号: 2-s2.0-85050805506
论文题名: Evolving Environmental and Geometric Controls on Columbia Glacier's Continued Retreat
作者: Enderlin E.M. ; O'Neel S. ; Bartholomaus T.C. ; Joughin I.
刊名: Journal of Geophysical Research: Earth Surface
ISSN: 21699003
出版年: 2018
卷: 123, 期: 7 起始页码: 1528
结束页码: 1545
语种: 英语
英文关键词: dynamics
; glacier
; glacier mass loss
; glacier retreat
; ice flow speed
; tidewater glacier
英文摘要: Geometry strongly controls the dynamic behavior of marine-terminating (tidewater) glaciers, significantly influencing advance and retreat cycles independent of climate. Yet the recent, nearly ubiquitous retreat of tidewater glaciers suggests that changes in atmospheric and oceanic forcing may also drive dynamic change. To isolate the influence of geometry on tidewater glacier dynamics, we analyzed detailed observational time series from 2012 to 2016 for two tidewater glaciers with shared dynamic histories and environmental forcing: Columbia Glacier and its former tributary (Post Glacier) in southcentral Alaska. We find that although terminus retreat has driven decadal-scale changes in dynamics of the Columbia-Post system, environmental factors contribute to short-term (i.e., seasonal) dynamic variability. In particular, analysis of force balance time series indicates that observed variations in speed result from seasonal changes to the subglacial hydrologic system and associated changes in basal drag. Variations in terminus position only drive noticeable speed change when the terminus retreats from regions of relatively high basal drag. In agreement with long-term analyses of Columbia Glacier, we find that terminus geometry can perturb the timing of seasonal ice flow patterns. Specifically, our data support the idea that retreat of a glacier terminus into deeper water is accompanied by a shift in the primary control on frontal ablation. Although our analysis focuses on two Alaskan glaciers, our data suggest that changes in the relative importance of surface meltwater and buoyancy effects on submarine melting and/or calving may manifest as a shift in terminus change seasonality and offer a mechanism to identify frontal ablation controls. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113636
Appears in Collections: 气候减缓与适应
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作者单位: Climate Change Institute, University of Maine, Orono, ME, United States; School of Earth and Climate Sciences, University of Maine, Orono, ME, United States; USGS Alaska Science Center, Anchorage, AK, United States; Department of Geological Sciences, University of Idaho, Moscow, ID, United States; Applied Physics Laboratory, University of Washington, Seattle, WA, United States
Recommended Citation:
Enderlin E.M.,O'Neel S.,Bartholomaus T.C.,et al. Evolving Environmental and Geometric Controls on Columbia Glacier's Continued Retreat[J]. Journal of Geophysical Research: Earth Surface,2018-01-01,123(7)