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Impacts of canonical and Modoki El Niño on tropical Atlantic SST
Author(s) -
Amaya Dillon J.,
Foltz Gregory R.
Publication year - 2014
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2013jc009476
Subject(s) - tropical atlantic , sea surface temperature , teleconnection , climatology , atlantic equatorial mode , kelvin wave , environmental science , gulf stream , tropical wave , tropics , oceanography , atlantic multidecadal oscillation , atmospheric sciences , geology , tropical cyclone , biology , ecology , el niño southern oscillation
The impacts of canonical and Modoki El Niño on tropical Atlantic sea surface temperature (SST) are quantified using composite analysis. Results show that El Niño Modoki fails to produce significant warming in the tropical Atlantic, in contrast to the well known warming following canonical El Niño events. El Niño Modoki instead induces significant cooling in the northeastern tropical Atlantic and near‐neutral conditions elsewhere in the tropical Atlantic. It is shown that the difference in SST response stems primarily from a much stronger Pacific/North American (PNA) teleconnection pattern and stronger atmospheric Kelvin wave response during canonical events compared to Modoki. The stronger PNA pattern and Kelvin waves during canonical events generate anomalously weak surface winds in the tropical North Atlantic, driving anomalously weak evaporative cooling and warmer SSTs. Past research has shown significant decadal variability in the frequency of noncanonical El Niños relative to canonical events. If such variability continues, it is likely that the impact of El Niño on tropical Atlantic SST will also fluctuate from one decade to the next.