气候变化领域集成服务门户(CCPortal): Combined diurnal variations of discharge and hydrochemistry of the Isunnguata Sermia outlet, Greenland Ice Sheet

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DOI	10.5194/tc-11-1131-2017
	Combined diurnal variations of discharge and hydrochemistry of the Isunnguata Sermia outlet, Greenland Ice Sheet
	Graly J.; Harrington J.; Humphrey N.
发表日期	2017
ISSN	19940416
卷号	11 期号:3
英文摘要	In order to examine daily cycles in meltwater routing and storage in the Isunnguata Sermia outlet of the Greenland Ice Sheet, variations in outlet stream discharge and in major element hydrochemistry were assessed over a 6-day period in July 2013. Over 4 days, discharge was assessed from hourly photography of the outlet from multiple vantages, including where midstream naled ice provided a natural gauge. pH, electrical conductivity, suspended sediment, and major element and anion chemistry were measured in samples of stream water collected every 3 h. Photography and stream observations reveal that although river width and stage have only slight diurnal variation, there are large diurnal changes in discharge shown by the doubling in width of what we term the "active channel", which is characterized by large standing waves and fast flow. The concentration of dissolved solutes follows a sinusoidal diurnal cycle, except for large and variable increases in dissolved solutes during the stream's waning flow. Solute concentrations vary by ∼30% between diurnal minima and maxima. Discharge maxima and minima lag temperature and surface melt by 3-7 h; diurnal solute concentration minima and maxima lag discharge by 3-6 h. This phase shift between discharge and solute concentration suggests that during high flow, water is either encountering more rock material or is stored in longer contact with rock material. We suggest that expansion of a distributed subglacial hydrologic network into seldom accessed regions during high flow could account for these phenomena, and for a spike of partial silicate reaction products during waning flow, which itself suggests a pressure threshold-triggered release of stored water. © Author(s) 2017.
学科领域	concentration (composition); diurnal variation; electrical conductivity; hydrogeochemistry; meltwater; river discharge; silicate; solute; temperature profile; Arctic; Greenland; Greenland Ice Sheet; Isunguata Sermia
语种	英语
scopus关键词	concentration (composition); diurnal variation; electrical conductivity; hydrogeochemistry; meltwater; river discharge; silicate; solute; temperature profile; Arctic; Greenland; Greenland Ice Sheet; Isunguata Sermia
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/119400
作者单位	Department of Geology and Geophysics, University of Wyoming, 1000 E. University Ave., Laramie, WY 82071, United States
推荐引用方式 GB/T 7714	Graly J.,Harrington J.,Humphrey N.. Combined diurnal variations of discharge and hydrochemistry of the Isunnguata Sermia outlet, Greenland Ice Sheet[J],2017,11(3).
APA	Graly J.,Harrington J.,&Humphrey N..(2017).Combined diurnal variations of discharge and hydrochemistry of the Isunnguata Sermia outlet, Greenland Ice Sheet.Cryosphere,11(3).
MLA	Graly J.,et al."Combined diurnal variations of discharge and hydrochemistry of the Isunnguata Sermia outlet, Greenland Ice Sheet".Cryosphere 11.3(2017).