Publications des scientifiques de l'IRD

Lee Y. K., Yeh S. W., Dewitte Boris, Moon B. K., Jhun J. G. (2012). The influences of interannual stratification variability and wind stress forcing on ENSO before and after the 1976 climate shift. Theoretical and Applied Climatology, 107 (3-4), p. 623-631. ISSN 0177-798X.

Titre du document
The influences of interannual stratification variability and wind stress forcing on ENSO before and after the 1976 climate shift
Année de publication
2012
Type de document
Article référencé dans le Web of Science WOS:000300082600025
Auteurs
Lee Y. K., Yeh S. W., Dewitte Boris, Moon B. K., Jhun J. G.
Source
Theoretical and Applied Climatology, 2012, 107 (3-4), p. 623-631 ISSN 0177-798X
In order to understand the change in oceanic variability associated with the climate shift of the mid-1970s, we analyze the contribution of momentum forcing to the leading baroclinic modes over the tropical Pacific using Simple Ocean Data Assimilation (SODA, version 2.0.2) for the period of 1958-1997. Specifically, we look at the statistical relationship between the wind projection coefficients and climate indices and attempt to provide a physical explanation for the observed changes. It is found that the wind stress projection coefficients according to the oceanic baroclinic modes are different in terms of their magnitude and phase in the tropical Pacific, reflecting a specific forcing associated with each mode before and after the 1976 climate shift. Compared to that before the 1970s, the first baroclinic mode is had a greater effect on the interannual sea surface temperature due to equatorial wave dynamics, and there was an increased delayed response of the second baroclinic mode variability to the interannual atmospheric forcing after the late 1970s. This reflects changes in ENSO feedback processes associated with the climate shift. Our analysis further indicates that, after the late 1970s, there was a decrease in the wind stress forcing projecting onto the Ekman layer, which is associated with increased mixed-layer depth. This result suggests that the changes in the ENSO properties before and after the late 1970s are largely associated with the changes in the way in which the wind stress forcing is dynamically projected onto the surface layer of the tropical Pacific Ocean over interannual timescales.
Plan de classement
Limnologie physique / Océanographie physique [032]
Localisation
Fonds IRD [F B010054387]
Identifiant IRD
fdi:010054387
Contact