Changes in the zonal propagation of El Niño-related SST anomalies: a possible link to the PDO
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Long-term variability of El Niño (EN) cycle has been the topic of several studies, mainly because of its impacts on climate around the globe. This variability has been mainly described by changes in the intensity and frequency of EN events. In this study, interdecadal changes in the zonal evolution of EN-related sea surface temperature anomalies (SSTA) and their possible link with a well-known mode of Pacific interdecadal variability are analyzed. EN events are classified according to the sense of zonal propagation of SSTA along the equatorial Pacific during the period 1900–2012. As a result, two types of EN are defined: eastward-directed and westward-directed EN. It is found that EN-related SSTA preferably evolves to the east (west) during the warm (cold) phase of the Pacific Decadal Oscillation. Hence, this study offers new insights into the possible causes of long-term EN changes.
KeywordsPacific Decadal Oscillation Zonal Propagation Equatorial Pacific Ocean Pacific Decadal Oscillation Index Pacific Decadal Oscillation Phase
The gridded NOAA_ERSST_V3 dataset was provided by the NOAA/OAR/ESRL PSD, Boulder, CO, USA, at http://www.esrl.noaa.gov/psd/. Time series of the PDO index were provided by the Nate Mantua Web site at JISAO (http://jisao.washington.edu/pdo/). This study was partially supported by grant PICT-2007-00400 from the National Scientific and Technological Agency (ANPCyT) and grant PIP 112-20080-00444 from the National Research Council (CONICET), Argentina.
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