气候变化领域集成服务门户(CCPortal): Asynchronous warming and δ18O evolution of deep Atlantic water masses during the last deglaciation

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DOI	10.1073/pnas.1704512114
	Asynchronous warming and δ18O evolution of deep Atlantic water masses during the last deglaciation
	Zhang J.; Liu Z.; Brady E.C.; Oppo D.W.; Clark P.U.; Jahn A.; Marcott S.A.; Lindsay K.
发表日期	2017
ISSN	0027-8424
起始页码	11075
结束页码	11080
卷号	114 期号:42
英文摘要	The large-scale reorganization of deep ocean circulation in the Atlantic involving changes in North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) played a critical role in regulating hemispheric and global climate during the last deglaciation. However, changes in the relative contributions of NADW and AABW and their properties are poorly constrained by marine records, including δ18O of benthic foraminiferal calcite (δ18Oc). Here, we use an isotope-enabled ocean general circulation model with realistic geometry and forcing conditions to simulate the deglacial water mass and δ18O evolution. Model results suggest that, in response to North Atlantic freshwater forcing during the early phase of the last deglaciation, NADW nearly collapses, while AABW mildly weakens. Rather than reflecting changes in NADW or AABW properties caused by freshwater input as suggested previously, the observed phasing difference of deep δ18Oc likely reflects early warming of the deep northern North Atlantic by ∼1.4 °C, while deep Southern Ocean temperature remains largely unchanged. We propose a thermodynamic mechanism to explain the early warming in the North Atlantic, featuring a strong middepth warming and enhanced downward heat flux via vertical mixing. Our results emphasize that the way that ocean circulation affects heat, a dynamic tracer, is considerably different from how it affects passive tracers, like δ18O, and call for caution when inferring water mass changes from δ18Oc records while assuming uniform changes in deep temperatures. © 2017, National Academy of Sciences. All rights reserved.
英文关键词	Atlantic water masses; Deep ocean warming; Last deglaciation; Oxygen isotopes
语种	英语
scopus关键词	oxygen 18; advection; Article; Atlantic Ocean; deglaciation; greenhouse effect; mass; North Atlantic deep water; oxygen evolution; priority journal; thermodynamics; water temperature
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160587
作者单位	Zhang, J., Center for Climatic Research, University of Wisconsin–Madison, Madison, WI 53706, United States, Department of Atmospheric and Oceanic Sciences, University of Wisconsin–Madison, Madison, WI 53706, United States, Computational Physics and Methods (CCS-2), Center for Nonlinear Studies (CNLS), Los Alamos National Laboratory, Los Alamos, NM 87545, United States; Liu, Z., Center for Climatic Research, University of Wisconsin–Madison, Madison, WI 53706, United States, Department of Atmospheric and Oceanic Sciences, University of Wisconsin–Madison, Madison, WI 53706, United States, Atmospheric Science Program, Department of Geography, Ohio State University, Columbus, OH 43210, United States; Brady, E.C., Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80307, United States; Oppo, D.W., Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States; Clark, P.U., College of Earth, Ocean, and Atmospheric S...
推荐引用方式 GB/T 7714	Zhang J.,Liu Z.,Brady E.C.,et al. Asynchronous warming and δ18O evolution of deep Atlantic water masses during the last deglaciation[J],2017,114(42).
APA	Zhang J..,Liu Z..,Brady E.C..,Oppo D.W..,Clark P.U..,...&Lindsay K..(2017).Asynchronous warming and δ18O evolution of deep Atlantic water masses during the last deglaciation.Proceedings of the National Academy of Sciences of the United States of America,114(42).
MLA	Zhang J.,et al."Asynchronous warming and δ18O evolution of deep Atlantic water masses during the last deglaciation".Proceedings of the National Academy of Sciences of the United States of America 114.42(2017).