DOI: 10.1029/2018GB005987
论文题名: Mechanisms of Low-Frequency Oxygen Variability in the North Pacific
作者: Ito T. ; Long M.C. ; Deutsch C. ; Minobe S. ; Sun D.
刊名: Global Biogeochemical Cycles
ISSN: 0886-6236
EISSN: 1944-9224
出版年: 2019
卷: 33, 期: 2 语种: 英语
英文关键词: annual variation
; biogeochemistry
; climate change
; climate modeling
; database
; decadal variation
; dissolved oxygen
; hindcasting
; mixed layer
; Pacific Decadal Oscillation
; sampling
; simulation
; upper ocean
; ventilation
; water column
; Pacific Ocean
; Pacific Ocean (North)
学科: biogeochemistry
; CESM
; climate variability
; ocean deoxygenation
; oxygen cycle
; World Ocean Database
中文摘要: This study investigates the mechanisms of interannual and decadal variability of dissolved oxygen (O 2 ) in the North Pacific using historical observations and a hindcast simulation using the Community Earth System Model. The simulated variability of upper ocean (200 m) O 2 is moderately correlated with observations where sampling density is relatively high. The dominant mode of O 2 variability explains 24.8% of the variance and is significantly correlated with the Pacific Decadal Oscillation (PDO) index (r = 0.68). Two primary mechanisms are hypothesized by which the PDO controls upper ocean O 2 variability. Vertical movement of isopycnals (“heave”) drives O 2 variations in the deep tropics; isopycnal surfaces are depressed in the eastern tropics under the positive (El Niño-like) phase of PDO, leading to O 2 increases in the upper water column. In contrast to the tropics, changes in subduction are the primary control on extratropical O 2 variability. These hypotheses are tested by contrasting O 2 anomalies with the heave-induced component of variability calculated from potential density anomalies. Isopycnal heave is the leading control on O 2 variability in the tropics, but heave alone cannot fully explain the amplitude of tropical O 2 variability, likely indicating reinforcing changes from the biological O 2 consumption. Midlatitude O 2 variability indeed reflects ocean ventilation downstream of the subduction region where O 2 anomalies are correlated with the depth of winter mixed layer. These mechanisms, synchronized with the PDO, yield a basin-scale pattern of O 2 variability that are comparable in magnitude to the projected rates of ocean deoxygenation in this century under “unchecked” emission scenario. ©2019. American Geophysical Union. All Rights Reserved.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/160154
Appears in Collections: 气候变化与战略
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作者单位: School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, United States; Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO, United States; School of Oceanography, University of Washington, Seattle, WA, United States; Department of Natural History Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan; Department of Earth and Planetary Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
Recommended Citation:
Ito T.,Long M.C.,Deutsch C.,et al. Mechanisms of Low-Frequency Oxygen Variability in the North Pacific[J]. Global Biogeochemical Cycles,2019-01-01,33(2)