气候变化领域集成服务门户(CCPortal): Key role of diabatic processes in regulating warm water volume variability over ENSO events

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DOI	10.1175/JCLI-D-20-0198.1
	Key role of diabatic processes in regulating warm water volume variability over ENSO events
	Huguenin M.F.; Holmes R.M.; England M.H.
发表日期	2020
ISSN	0894-8755
起始页码	9945
结束页码	9964
卷号	33 期号:22
英文摘要	The equatorial Pacific warm water volume (WWV), defined as the volume of water warmer than 208C near the equator, is a key predictor for El Niño–Southern Oscillation (ENSO), and yet much about the individual processes that influence it remains unknown. In this study, we conduct idealized ENSO simulations forced with symmetric El Niño– and La Niña–associated atmospheric anomalies as well as a historical 1979–2016 hindcast simulation. We use the water mass transformation framework to examine the individual contributions of diabatic and adiabatic processes to changes in WWV. We find that in both sets of simulations, El Niño’s discharge and La Niña’s recharge periods are initiated by diabatic fluxes of volume across the 208C isotherm associated with changes in surface forcing and vertical mixing. Changes in adiabatic horizontal volume transport above 208C between the equator and subtropical latitudes dominate at a later stage. While surface forcing and vertical mixing deplete WWV during El Niño, surface forcing during La Niña drives a large increase partially compensated for by a decrease driven by vertical mixing. On average, the ratio of diabatic to adiabatic contributions to changes in WWV during El Niño is about 40% to 60%; during La Niña this ratio changes to 75% to 25%. The increased importance of the diabatic processes during La Niña, especially the surface heat fluxes, is linked to the shoaling of the 208C isotherm in the eastern equatorial Pacific and is a major source of asymmetry between the two ENSO phases, even in the idealized simulations where the wind forcing and adiabatic fluxes are symmetric. © 2020 American Meteorological Society.
英文关键词	Atmospheric pressure; Climatology; Heat flux; Isotherms; Mixing; Adiabatic process; Atmospheric anomaly; Eastern equatorial Pacific; Equatorial Pacific; Southern oscillation; Subtropical latitudes; Surface heat fluxes; Water mass transformation; Lanthanum; annual variation; climate modeling; diabatic process; El Nino; El Nino-Southern Oscillation; La Nina; oceanic circulation; volume transport
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/171078
作者单位	Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland; Climate Change Research Centre, ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, NSW, Australia; School of Mathematics and Statistics, University of New South Wales, Sydney, NSW, Australia
推荐引用方式 GB/T 7714	Huguenin M.F.,Holmes R.M.,England M.H.. Key role of diabatic processes in regulating warm water volume variability over ENSO events[J],2020,33(22).
APA	Huguenin M.F.,Holmes R.M.,&England M.H..(2020).Key role of diabatic processes in regulating warm water volume variability over ENSO events.Journal of Climate,33(22).
MLA	Huguenin M.F.,et al."Key role of diabatic processes in regulating warm water volume variability over ENSO events".Journal of Climate 33.22(2020).