气候变化领域集成服务门户(CCPortal): Ocean Circulation and Variability Beneath Nioghalvfjerdsbræ (79 North Glacier) Ice Tongue

CCPortal

DOI	10.1029/2020JC016091
	Ocean Circulation and Variability Beneath Nioghalvfjerdsbræ (79 North Glacier) Ice Tongue
	Lindeman M.R.; Straneo F.; Wilson N.J.; Toole J.M.; Krishfield R.A.; Beaird N.L.; Kanzow T.; Schaffer J.
发表日期	2020
ISSN	21699275
卷号	125 期号:8
英文摘要	The floating ice tongue of 79 North Glacier, a major outlet glacier of the Northeast Greenland Ice Stream, has thinned by 30% since 1999. Earlier studies have indicated that long-term warming of Atlantic Intermediate Water (AIW) is likely driving increased basal melt, causing the observed thinning. Still, limited ocean measurements in 79 North Fjord beneath the ice tongue have made it difficult to test this hypothesis. Here we use data from an Ice Tethered Mooring (ITM) deployed in a rift in the ice tongue from August 2016 to July 2017 to show that the subannual AIW temperature variability is smaller than the observed interannual variability, supporting the conclusion that AIW has warmed over the period of ice tongue thinning. In July 2017, the AIW at 500 m depth in the ice tongue cavity reached a maximum recorded temperature of 1.5°C. Velocity measurements reveal weak tides and a mean overturning circulation, which is likely seasonally enhanced by subglacial runoff discharged at the grounding line. Deep inflow of AIW and shallow export of melt-modified water persist throughout the record, indicating year-round basal melting of the ice tongue. Comparison with a mooring outside of the cavity suggests a rapid exchange between the cavity and continental shelf. Warming observed during 2016–2017 is estimated to drive a 33 ± 20% increase in basal melt rate near the ice tongue terminus and a 14 ± 2% increase near the grounding line if sustained. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	79 North; basal melt; fjord; Greenland; ice ocean interaction; ice shelf
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186717
作者单位	Scripps Institution of Oceanography, University of California, San Diego, CA, United States; Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, United States; Alfred-Wegener-Institut Helmholtz-Zentrum flür Polar- und Meeresforschung, Bremerhaven, Germany; Department of Physics and Mechanical Engineering, University of Bremen, Bremen, Germany
推荐引用方式 GB/T 7714	Lindeman M.R.,Straneo F.,Wilson N.J.,et al. Ocean Circulation and Variability Beneath Nioghalvfjerdsbræ (79 North Glacier) Ice Tongue[J],2020,125(8).
APA	Lindeman M.R..,Straneo F..,Wilson N.J..,Toole J.M..,Krishfield R.A..,...&Schaffer J..(2020).Ocean Circulation and Variability Beneath Nioghalvfjerdsbræ (79 North Glacier) Ice Tongue.Journal of Geophysical Research: Oceans,125(8).
MLA	Lindeman M.R.,et al."Ocean Circulation and Variability Beneath Nioghalvfjerdsbræ (79 North Glacier) Ice Tongue".Journal of Geophysical Research: Oceans 125.8(2020).