DOI: 10.5194/tc-11-1131-2017
Scopus记录号: 2-s2.0-85019167795
论文题名: Combined diurnal variations of discharge and hydrochemistry of the Isunnguata Sermia outlet, Greenland Ice Sheet
作者: Graly J ; , Harrington J ; , Humphrey N
刊名: Cryosphere
ISSN: 19940416
出版年: 2017
卷: 11, 期: 3 起始页码: 1131
结束页码: 1140
语种: 英语
英文关键词: concentration (composition)
; diurnal variation
; electrical conductivity
; hydrogeochemistry
; meltwater
; river discharge
; silicate
; solute
; temperature profile
; Arctic
; Greenland
; Greenland Ice Sheet
; Isunguata Sermia
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75559
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Department of Geology and Geophysics, University of Wyoming, 1000 E. University Ave., Laramie, WY, United States
Recommended Citation:
Graly J,, Harrington J,, Humphrey N. Combined diurnal variations of discharge and hydrochemistry of the Isunnguata Sermia outlet, Greenland Ice Sheet[J]. Cryosphere,2017-01-01,11(3)