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North‐south asymmetry of warm water volume transport related with El Niño variability
Author(s) -
Ishida Akio,
Kashino Yuji,
Hosoda Shigeki,
Ando Kentaro
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl034858
Subject(s) - pycnocline , geology , zonal and meridional , climatology , boundary current , ekman transport , asymmetry , atmospheric sciences , oceanography , ocean current , upwelling , physics , quantum mechanics
A better understanding of variability in the volume of warm water in the equatorial Pacific pycnocline (warm water volume, or WWV) is critical to understanding El Niño‐Southern Oscillation (ENSO) variability. We have investigated the meridional WWV transport in the Northern (NH) and Southern Hemispheres (SH) using a high‐resolution general circulation model. The transport in the western boundary region compensates the interior transport in the SH, where Sverdrup balance holds approximately. In contrast, such compensation does not hold in the NH, because the boundary transport lags interior transport by about 7 months. Hence, the WWV exchange in the NH has more impact on the recharge‐discharge of the equatorial WWV. The north‐south asymmetry of the WWV transport, which is interpreted based on the linear Rossby theory, is related with the southward migration of westerly wind and the negative wind curl over the northwestern off‐equatorial region after the mature stage of ENSO.