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Intensification of Westerly Wind Bursts Caused by the Coupling of the Madden‐Julian Oscillation to SST During El Niño Onset and Development
Author(s) -
Liang Yu,
Fedorov Alexey V.,
Haertel Patrick
Publication year - 2021
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 - 10.1029/2020gl089395
Subject(s) - madden–julian oscillation , equator , climatology , anomaly (physics) , geology , southern hemisphere , sea surface temperature , northern hemisphere , westerlies , convection , oscillation (cell signaling) , atmospheric sciences , latitude , meteorology , physics , geodesy , condensed matter physics , biology , genetics
The Madden‐Julian Oscillation (MJO) plays an important role in El Niño dynamics in connection with westerly wind bursts (WWBs) that occur in the equatorial Pacific; however, our understanding of the relationship between these climate phenomena remains incomplete. Here, we use a Lagrangian Atmospheric Model (LAM) to examine the response of the MJO and resulting WWBs to sea surface temperature (SST) anomalies similar to those observed during the onset and development of El Niño. We find that when a localized SST anomaly (≤1°C) is imposed in the western‐central equatorial Pacific between December and April (mimicking El Niño onset), the MJO convective envelope shifts from the southern hemisphere toward the equator. When an SST anomaly (≤1.5°C) is imposed in the central‐eastern equatorial Pacific between May and November (mimicking El Niño development), the MJO weakens in the northwestern Pacific, but strengthens in the central equatorial Pacific. In both experiments, the ensuing changes enhance MJO activity along the equator, facilitating WWBs.