DOI: 10.5194/tc-15-3355-2021
论文题名: Surges of Harald Moltke Bræ, north-western Greenland: Seasonal modulation and initiation at the terminus
作者: Müller L. ; Horwath M. ; Scheinert M. ; Mayer C. ; Ebermann B. ; Floricioiu D. ; Krieger L. ; Rosenau R. ; Vijay S.
刊名: Cryosphere
ISSN: 19940416
出版年: 2021
卷: 15, 期: 7 起始页码: 3355
结束页码: 3375
语种: 英语
英文关键词: flow velocity
; glacier dynamics
; ice flow
; ice thickness
; meltwater
; satellite imagery
; seasonal variation
; Arctic
; Greenland
英文摘要: Harald Moltke Bræ, a marine-terminating glacier in north-western Greenland, shows episodic surges. A recent surge from 2013 to 2019 lasted significantly longer (6 years) than previously observed surges (2-4 years) and exhibits a pronounced seasonality with flow velocities varying by 1 order of magnitude (between about 0.5 and 10gmgd-1) in the course of a year. During this 6-year period, the seasonal velocity always peaked in the early melt season and decreased abruptly when meltwater runoff was maximum. Our data suggest that the seasonality has been similar during previous surges. Furthermore, the analysis of satellite images and digital elevation models shows that the surge from 2013 to 2019 was preceded by a rapid frontal retreat and a pronounced thinning at the glacier front (30gm within 3 years). We discuss possible causal mechanisms of the seasonally modulated surge behaviour by examining various system-inherent factors (e.g. glacier geometry) and external factors (e.g. surface mass balance). The seasonality may be caused by a transition of an inefficient subglacial system to an efficient one, as known for many glaciers in Greenland. The patterns of flow velocity and ice thickness variations indicate that the surges are initiated at the terminus and develop through an up-glacier propagation of ice flow acceleration. Possibly, this is facilitated by a simultaneous up-glacier spreading of surface crevasses and weakening of subglacial till. Once a large part of the ablation zone has accelerated, conditions may favour substantial seasonal flow acceleration through seasonally changing meltwater availability. Thus, the seasonal amplitude remains high for 2 or more years until the fast ice flow has flattened the ice surface and the glacier stabilizes again. © 2021 Lukas Müller et al. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164766
Appears in Collections: 气候变化与战略
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作者单位: Technische Universität Dresden, Institut für Planetare Geodäsie, Dresden, Germany; Institute of Geodesy and Photogrammetry, ETH Zurich, Zurich, Switzerland; Bavarian Academy of Sciences and Humanities, Munich, Germany; German Aerospace Center, Wessling, Germany; DTU Space - National Space Institute, Kongens Lyngby, Denmark; Byrd Polar and Climate Research Center, Columbus, United States
Recommended Citation:
Müller L.,Horwath M.,Scheinert M.,et al. Surges of Harald Moltke Bræ, north-western Greenland: Seasonal modulation and initiation at the terminus[J]. Cryosphere,2021-01-01,15(7)