DOI: 10.5194/tc-14-1951-2020
论文题名: Surface emergence of glacial plumes determined by fjord stratification
作者: De Andrés E. ; Slater D.A. ; Straneo F. ; Otero J. ; Das S. ; Navarro F.
刊名: Cryosphere
ISSN: 19940416
出版年: 2020
卷: 14, 期: 6 起始页码: 1951
结束页码: 1969
语种: 英语
英文关键词: accumulation
; carbon dioxide
; discharge
; fjord
; ice sheet
; melting
; meltwater
; sediment-water interface
; subglacial deposit
; tidewater glacier
; trapping
; Arctic
; Greenland
; Greenland Ice Sheet
英文摘要: Meltwater and sediment-laden plumes at tidewater glaciers, resulting from the localized subglacial discharge of surface melt, influence submarine melting of the glacier and the delivery of nutrients to the fjord's surface waters. It is usually assumed that increased subglacial discharge will promote the surfacing of these plumes. Here, at a western Greenland tidewater glacier, we investigate the counterintuitive observation of a non-surfacing plume in July 2012 (a year of record surface melting) compared to the surfacing of the plume in July 2013 (an average melt year). We combine oceanographic observations, subglacial discharge estimates and an idealized plume model to explain the observed plumes' behavior and evaluate the relative impact of fjord stratification and subglacial discharge on plume dynamics. We find that increased fjord stratification prevented the plume from surfacing in 2012, show that the fjord was more stratified in 2012 due to increased freshwater content and speculate that this arose from an accumulation of ice sheet surface meltwater in the fjord in this record melt year. By developing theoretical scalings, we show that fjord stratification in general exerts a dominant control on plume vertical extent (and thus surface expression), so that studies using plume surface expression as a means of diagnosing variability in glacial processes should account for possible changes in stratification. We introduce the idea that, despite projections of increased surface melting over Greenland, the appearance of plumes at the fjord surface could in the future become less common if the increased freshwater acts to stratify fjords around the Greenland ice sheet. We discuss the implications of our findings for nutrient fluxes, trapping of atmospheric CO2 and the properties of water exported from Greenland's fjords. © Author(s) 2020. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164439
Appears in Collections: 气候变化与战略
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作者单位: Department of Applied Mathematics, ETSI de Telecomunicación, Universidad Politécnica de Madrid, Madrid, Spain; Scripps Institution of Oceanography, University of California San Diego, San Diego, CA, United States; School of Geography and Sustainable Development, University of St. Andrews, St. Andrews, United Kingdom; Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
Recommended Citation:
De Andrés E.,Slater D.A.,Straneo F.,et al. Surface emergence of glacial plumes determined by fjord stratification[J]. Cryosphere,2020-01-01,14(6)