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Diversity of Pacific Meridional Mode and its distinct impacts on El Niño-Southern Oscillation
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  • Jiuwei Zhao,
  • Jong-Seong Kug,
  • Jae-Heung Park,
  • Soon-Il An
Jiuwei Zhao
Nanjing University of Information Science and Technology
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Jong-Seong Kug

Corresponding Author:[email protected]

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Jae-Heung Park
Pohang University of Science and Technology
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Soon-Il An
Yonsei University
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Numerous studies have demonstrated that the Pacific Meridional Mode (PMM) plays a vital role in determining El Niño-Southern Oscillation (ENSO) events in the following winter season. However, little attention has been given to significant differences among the spatial patterns of the PMM. Here we show that the PMM exhibits a large diversity in spatial patterns, leading to distinct impacts on ENSO. Based on objective clustering analysis, two distinct spatial patterns of the PMM are detected. Cluster 1 (C1) PMM exhibits a strong sea surface temperature dipole over the subtropical eastern Pacific and mid-latitude central Pacific whereas cluster 2 (C2) features a classic dipole over the subtropical eastern Pacific and equatorial cold tongue regions. We find that the C1 PMM is strongly linked to ENSO events while the C2 PMM has no statistically significant relations with following ENSO. This gives new implications for ENSO dynamics and predictions.