气候变化领域集成服务门户(CCPortal): The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State

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DOI	10.1175/JCLI-D-20-0049.1
	The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State
	Zhang L.; Delworth T.L.; Cooke W.; Goosse H.; Bushuk M.; Morioka Y.; Yang X.
发表日期	2021
ISSN	0894-8755
起始页码	1061
结束页码	1080
卷号	34 期号:3
英文摘要	Previous studies have shown the existence of internal multidecadal variability in the Southern Ocean using multiple climate models. This variability, associated with deep ocean convection, can have significant climate impacts. In this work, we use sensitivity studies based on Geophysical Fluid Dynamics Laboratory (GFDL) models to investigate the linkage of this internal variability with the background ocean mean state. We find that mean ocean stratification in the subpolar region that is dominated by mean salinity influences whether this variability occurs, as well as its time scale. The weakening of background stratification favors the occurrence of deep convection. For background stratification states in which the low-frequency variability occurs, weaker ocean stratification corresponds to shorter periods of variability and vice versa. The amplitude of convection variability is largely determined by the amount of heat that can accumulate in the subsurface ocean during periods of the oscillation without deep convection. A larger accumulation of heat in the subsurface reservoir corresponds to a larger amplitude of variability. The subsurface heat buildup is a balance between advection that supplies heat to the reservoir and vertical mixing/convection that depletes it. Subsurface heat accumulation can be intensified both by an enhanced horizontal temperature advection by the Weddell Gyre and by an enhanced ocean stratification leading to reduced vertical mixing and surface heat loss. The paleoclimate records over Antarctica indicate that this multidecadal variability has very likely happened in past climates and that the period of this variability may shift with different climate background mean state. Ó 2021 American Meteorological Society.
英文关键词	Advection; Climate models; Mixing; Natural convection; American meteorological societies; Deep ocean convection; Geophysical fluid dynamics laboratories; Internal variability; Low frequency variability; Multidecadal variability; Ocean stratification; Paleoclimate records; Oceanography
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/170927
作者单位	NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, NJ, United States; University Corporation for Atmospheric Research, Boulder, CO, United States; Earth and Life Institute, Université de Louvain, Louvain-la-Neuve, Belgium; Application Laboratory, VAiG, JAMSTEC, Yokohama, Japan
推荐引用方式 GB/T 7714	Zhang L.,Delworth T.L.,Cooke W.,et al. The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State[J],2021,34(3).
APA	Zhang L..,Delworth T.L..,Cooke W..,Goosse H..,Bushuk M..,...&Yang X..(2021).The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State.Journal of Climate,34(3).
MLA	Zhang L.,et al."The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State".Journal of Climate 34.3(2021).