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| Titel |
On the role of oceanic entrainment temperature (Te) in decadal changes of El Niño/Southern Oscillation |
| VerfasserIn |
J. Zhu, G. Zhou, R.-H. Zhang, Z. Sun |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 29, no. 3 ; Nr. 29, no. 3 (2011-03-10), S.529-540 |
| Datensatznummer |
250016989
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| Publikation (Nr.) |
 copernicus.org/angeo-29-529-2011.pdf |
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| Zusammenfassung |
| The role of decadal changes in ocean thermal structure in modulating El
Niño/Southern Oscillation (ENSO) properties was examined using a hybrid
coupled model (HCM), consisting of a statistical atmospheric model and an
oceanic general circulation model (OGCM) with an explicitly embedded
empirical parameterization for the temperature of subsurface water entrained
into the mixed layer (Te), which was constructed via an EOF analysis of
model-based historical data. Using the empirical Te models constructed
from two subperiods, 1963–1979 (Te63−79) and 1980–1996
(Te80−96), the coupled system exhibits striking different
properties of interannual variability, including oscillation periods and the
propagation characteristic of sea surface temperature anomalies (SSTAs)
along the equator. In the Te63−79 run, the model features a 2–3 yr
oscillation and a westward propagation of SSTAs along the equator, while in
the Te80−96 run, it is characterized by a 4–5 yr oscillation and an
eastward propagation. Furthermore, a Lag Covariance Analysis (LCOA) was
utilized to illustrate the leading physical processes responsible for
decadal change in SST. It is shown that the change in the structure of
Te acts to modulate the relative strength of the zonal advective and
thermocline feedbacks in the coupled system, leading to changes in ENSO
properties. Two additional sensitive experiments were conducted to further
illustrate the respective roles of the changes in ocean mean states and in
Te in modulating ENSO behaviors. These decadal changes in the simulated
ENSO properties are consistent with the observed shift occurred in the late
1970s and a previous simulation performed with an intermediate coupled model
(ICM) described in Zhang and Busalacchi (2005), indicating a dominant role
Te plays in decadal ENSO changes. |
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