DOI: 10.1007/s00382-015-2655-5
Scopus记录号: 2-s2.0-84959121017
论文题名: Role of subsurface entrainment temperature (Te) in the onset of El Niño events, as represented in an intermediate coupled model
作者: Zhang R.-H. ; Gao C.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 46, 期: 2017-05-06 起始页码: 1417
结束页码: 1435
语种: 英语
英文摘要: An improved intermediate coupled model (ICM) is described for use in ENSO-related modeling in the tropical Pacific, with ten baroclinic modes included in the vertical and horizonatally varying stratification taken into account. One crucial component of the model is the way in which the subsurface entrainment temperature in the surface mixed layer (Te) is explicitly used to determine the sea surface temperature (SST) variability. An optimized procedure is developed to depict Te using inverse modeling from an SST anomaly equation and its empirical relationship with the sea surface pressure variability. The coupled system realistically produces interannual variability associated with ENSO cycles, with a dominant 4-year oscillation. The onset and development of El Niño events from this ICM are examined in view of the well-known delayed oscillator paradigm; an example is given for the evolution of La Niña conditions in model year 2 to El Niño conditions in year 4. Right after a La Niña event (e.g., in year 2), there is a clear signature of reflections at the western boundary in early year 2, with related equatorial signals propagating eastward along the equator into the eastern basin in middle year 2. However, these reflected signals on the equator do not directly lead to an onset of an El Niño event at that time. Instead, approximately 1-year delay, a major El Niño event is seen to develop in the following year (late year 3), at a time when there is no reflected signal explicitly from the western boundary, indicating that the origin of the El Niño event cannot be directly ascribed to the reflection processes. Instead, Kelvin waves in the ocean that actually triggers the El Niño event in early year 3 are generated by interior wind anomalies near the date line that are associated with the first appearance of warm SST anomalies off the equator. Persisted Te anomalies off the equator in the western tropical Pacific initiate the warm SST anomaly near the date line along the North Equatorial Countercurrent region, which induces wind anomalies and an ocean–atmosphere coupling, leading to the El Niño event in year 4. The relevance of these ICM-based results to other onset mechanisms of El Niño and observations is also discussed. © 2015, The Author(s). 资助项目: NSFC, National Natural Science Foundation of China
; NSFC, National Natural Science Foundation of China
; NSFC, National Natural Science Foundation of China
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53803
Appears in Collections: 过去全球变化的重建
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作者单位: Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
Recommended Citation:
Zhang R.-H.,Gao C.. Role of subsurface entrainment temperature (Te) in the onset of El Niño events, as represented in an intermediate coupled model[J]. Climate Dynamics,2016-01-01,46(2017-05-06)