期刊名称：Journal of Advances in Modeling Earth Systems
电子版ISSN：1942-2466
出版年度：2020
卷号：12
期号：12
页码：1-28
DOI：10.1029/2019MS002022
出版社：John Wiley & Sons, Ltd.
摘要：This study presents a description of the El Niño–Southern Oscillation (ENSO) and Pacific
Decadal Variability (PDV) in a multicentury preindustrial simulation of the Community Earth System
Model Version 2 (CESM2). The model simulates several aspects of ENSO relatively well, including dominant
timescale, tropical and extratropical precursors, composite evolution of El Niño and La Niña events, and
ENSO teleconnections. The good model representation of ENSO spectral characteristics is consistent
with the spatial pattern of the anomalous equatorial zonal wind stress in the model, which results in the
correct adjustment timescale of the equatorial thermocline according to the delayed/recharge oscillator
paradigms, as also reflected in the realistic time evolution of the equatorial Warm Water Volume. PDV in the
model exhibits a pattern that is very similar to the observed, with realistic tropical and South Pacific
signatures which were much weaker in some of the CESM2 predecessor models. The tropical component of
PDV also shows an association with ENSO decadal modulation which is similar to that found in
observations. However, the ENSO amplitude is about 30% larger than observed in the preindustrial CESM2
simulation, and even larger in the historical ensemble, perhaps as a result of anthropogenic influences.
In contrast to observations, the largest variability is found in the central Pacific rather than in the eastern
Pacific, a discrepancy that somewhat hinders the model's ability to represent a full diversity in El Niño
spatial patterns and appears to be associated with an unrealistic confinement of the precipitation anomalies
to the western Pacific.
