气候变化领域集成服务门户(CCPortal): Surges of Harald Moltke Bræ, north-western Greenland: Seasonal modulation and initiation at the terminus

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DOI	10.5194/tc-15-3355-2021
	Surges of Harald Moltke Bræ, north-western Greenland: Seasonal modulation and initiation at the terminus
	Müller L.; Horwath M.; Scheinert M.; Mayer C.; Ebermann B.; Floricioiu D.; Krieger L.; Rosenau R.; Vijay S.
发表日期	2021
ISSN	19940416
起始页码	3355
结束页码	3375
卷号	15 期号:7
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.
英文关键词	flow velocity; glacier dynamics; ice flow; ice thickness; meltwater; satellite imagery; seasonal variation; Arctic; Greenland
语种	英语
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202388
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
推荐引用方式 GB/T 7714	Müller L.,Horwath M.,Scheinert M.,et al. Surges of Harald Moltke Bræ, north-western Greenland: Seasonal modulation and initiation at the terminus[J],2021,15(7).
APA	Müller L..,Horwath M..,Scheinert M..,Mayer C..,Ebermann B..,...&Vijay S..(2021).Surges of Harald Moltke Bræ, north-western Greenland: Seasonal modulation and initiation at the terminus.Cryosphere,15(7).
MLA	Müller L.,et al."Surges of Harald Moltke Bræ, north-western Greenland: Seasonal modulation and initiation at the terminus".Cryosphere 15.7(2021).