气候变化领域集成服务门户(CCPortal): Orbital modulation of ENSO seasonal phase locking

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DOI	10.1007/s00382-018-4382-1
	Orbital modulation of ENSO seasonal phase locking
	Lu Z.; Liu Z.
发表日期	2019
ISSN	0930-7575
起始页码	4329
结束页码	4350
卷号	52 期号:2020-07-08
英文摘要	Modern El Niño-Southern Oscillation (ENSO) events are characterized by their phase locking of variability to the seasonal cycle and tend to peak at the end of calendar year. Here, we show that in an idealized NCAR-CCSM3 simulation of the climate of the last 300,000 years, ENSO seasonal phase locking is shifted periodically following the precessional forcing: ENSO tends to peak in boreal winter when perihelion is near vernal equinox, but to peak in boreal summer when perihelion lies in between autumnal equinox and winter solstice. The mechanism for the change of ENSO’s phase locking is proposed to be caused by the change of seasonality of the growth rate, or the intensity of ocean–atmosphere feedbacks, of ENSO. It is found that the December peak of ‘winter ENSO’ is caused by the continuous growth of ENSO anomaly from June to November, while the May–June peak of ‘summer ENSO’ appears to be caused jointly by the seasonal shift of higher growth rate into spring and stronger stochastic noise towards the first half of the year. Furthermore, the change of the seasonal cycle of feedbacks is contributed predominantly by that of the thermodynamic damping. The summer peak of ENSO is proposed to be caused by the following mechanism. A perihelion in the late fall to early winter leads to a cooling of the surface eastern equatorial Pacific (EEP) due to reduced insolation in spring. This cooling, reinforced by an oceanic process, reduces the latent heat flux damping in spring, and therefore favors the growth of the eastern Pacific-like ENSO (as opposed to the central Pacific-like ENSO). This EEP cooling is also likely to generate more effective short wave-cloud-SST feedback and, in turn, increased instability. Ultimately, the weakened thermodynamic damping in spring, combined with relatively intensive stochastic forcing, benefits the subsequent summer peak of ENSO. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	ENSO; Ocean–atmosphere feedbacks; Orbital forcing; Phase locking
语种	英语
scopus关键词	air-sea interaction; damping; El Nino-Southern Oscillation; feedback mechanism; orbital forcing; seasonality; stochasticity; Pacific Ocean; Pacific Ocean (East)
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/146413
作者单位	Lab. Climate, Ocean and Atmosphere Studies, School of Physics, Peking University, Beijing, 100871, China; Department of Geography, Ohio State University, Columbus, OH 43210, United States; Department of Physical Geography and Ecosystem Science, Lund University, Lund, 22362, Sweden
推荐引用方式 GB/T 7714	Lu Z.,Liu Z.. Orbital modulation of ENSO seasonal phase locking[J],2019,52(2020-07-08).
APA	Lu Z.,&Liu Z..(2019).Orbital modulation of ENSO seasonal phase locking.Climate Dynamics,52(2020-07-08).
MLA	Lu Z.,et al."Orbital modulation of ENSO seasonal phase locking".Climate Dynamics 52.2020-07-08(2019).