气候变化领域集成服务门户(CCPortal): Revisiting the causal connection between the great salinity anomaly of the 1970s and the shutdown of Labrador sea deep convection

CCPortal

DOI	10.1175/JCLI-D-20-0327.1
	Revisiting the causal connection between the great salinity anomaly of the 1970s and the shutdown of Labrador sea deep convection
	Kim W.M.; Yeager S.; Danabasoglu G.
发表日期	2021
ISSN	0894-8755
起始页码	675
结束页码	696
卷号	34 期号:2
英文摘要	The Great Salinity Anomaly (GSA) of the 1970s is the most pronounced decadal-scale low-salinity event observed in the subpolar North Atlantic (SPNA). Using various simulations with the Community Earth System Model, here we offer an alternative view on some aspects of the GSA. Specifically, we examine the relative roles of reduced surface heat flux associated with the negative phase of the North Atlantic Oscillation (NAO) and extreme Fram Strait sea ice export (FSSIE) in the late 1960s as possible drivers of the shutdown of Labrador Sea (LS) deep convection. Through composite analysis of a long control simulation, the individual oceanic impacts of extreme FSSIE and surface heat flux events in the LS are isolated. A dominant role for the surface heat flux events for the suppression of convection and freshening in the interior LS is found, while the FSSIE events play a surprisingly minor role. The interior freshening results from reduced mixing of fresher upper ocean with saltier deep ocean. In addition, we find that the downstream propagation of the freshwater anomaly across the SPNA is potentially induced by the persistent negative NAO forcing in the 1960s through an adjustment of thermohaline circulation, with the extreme FSSIE-induced low-salinity anomaly mostly remaining in the boundary currents in the western SPNA. Our results suggest a prominent driving role of the NAO-related heat flux forcing for key aspects of the observed GSA, including the shutdown of LS convection and transbasin propagation of low-salinity waters. © 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
英文关键词	Atmospheric pressure; Ferroelectric RAM; Natural convection; Oceanography; Sea ice; Composite analysis; Control simulation; Earth system model; Low-salinity water; North Atlantic oscillations; Subpolar North Atlantic; Surface heat fluxes; Thermohaline circulations; Heat flux; decadal variation; freshwater input; meridional circulation; North Atlantic Oscillation; oceanic convection; overturn; sea surface salinity; Atlantic Ocean; Labrador Sea
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/170944
作者单位	Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO, United States
推荐引用方式 GB/T 7714	Kim W.M.,Yeager S.,Danabasoglu G.. Revisiting the causal connection between the great salinity anomaly of the 1970s and the shutdown of Labrador sea deep convection[J],2021,34(2).
APA	Kim W.M.,Yeager S.,&Danabasoglu G..(2021).Revisiting the causal connection between the great salinity anomaly of the 1970s and the shutdown of Labrador sea deep convection.Journal of Climate,34(2).
MLA	Kim W.M.,et al."Revisiting the causal connection between the great salinity anomaly of the 1970s and the shutdown of Labrador sea deep convection".Journal of Climate 34.2(2021).