气候变化领域集成服务门户(CCPortal): On the control of subantarctic stratification by the ocean circulation

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DOI	10.1007/s00382-020-05473-2
	On the control of subantarctic stratification by the ocean circulation
	Small R.J.; DuVivier A.K.; Whitt D.B.; Long M.C.; Grooms I.; Large W.G.
发表日期	2020
ISSN	0930-7575
英文摘要	A shallow mixed layer depth bias in Austral winter in the Subantarctic Zone is a common feature of Coupled Model Intercomparison Project (CMIP5) models, including the Community Earth System Model (CESM). The bias is related to other deficiencies in the model solution, including too-weak Subantarctic Mode water formation and excessive leakage of Agulhas waters into the Atlantic instead of into the Indian Ocean and Subantarctic Frontal Zone. This work investigates the hypothesis that the shallow bias is due to errors in the simulated ocean circulation. Results from a model with low resolution ocean component (1° grid) are compared against: (i) an experiment with an eddy resolving (0.1°) grid and (ii) experiments using the 1° grid and employing an adiabatic nudging of the ocean pressure field to observations that is referred to as a semi-prognostic method. For both the higher resolution and semi-prognostic experiments, improved horizontal advection of warm and salty water near the surface leads to a more realistic sea surface temperature (SST) and salinity front associated with the Agulhas Return Current and Antarctic Circumpolar Current. The warmer surface waters in the high-resolution model and semi-prognostic model lead to stronger air–sea heat loss, with a response of about 40 Wm−2 °C−1 in winter in the area of deep mixed layers. Budgets of the temperature and salinity stratification show that the deeper mixed layers in the high-resolution experiment are primarily a result of the increased surface heat loss, whereas in the semi-prognostic case salinity advection is the main factor leading to destabilization of the water column. Both results indicate that ocean circulation is a key factor in wintertime deep Southern Ocean mixing, associated with advection of water masses and air–sea feedbacks. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
语种	英语
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/145676
作者单位	Climate and Global Dynamics Division, National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305, United States; Department of Applied Mathematics, University of Colorado, Boulder, United States
推荐引用方式 GB/T 7714	Small R.J.,DuVivier A.K.,Whitt D.B.,et al. On the control of subantarctic stratification by the ocean circulation[J],2020.
APA	Small R.J.,DuVivier A.K.,Whitt D.B.,Long M.C.,Grooms I.,&Large W.G..(2020).On the control of subantarctic stratification by the ocean circulation.Climate Dynamics.
MLA	Small R.J.,et al."On the control of subantarctic stratification by the ocean circulation".Climate Dynamics (2020).