Japan Geoscience Union Meeting 2019

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[E] Poster

A (Atmospheric and Hydrospheric Sciences ) » A-OS Ocean Sciences & Ocean Environment

[A-OS09] Ocean Mixing Processes: Impact on Biogeochemistry, Climate and Ecosystem

Sun. May 26, 2019 3:30 PM - 5:00 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Ichiro Yasuda(Atmosphere and Ocean Research Institute, The University of Tokyo), Toshiyuki Hibiya(Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo), Jun Nishioka(Hokkaido University, Institute of low temperature sciences), Shin-ichi Ito(Atmosphere and Ocean Research Institute, The University of Tokyo)

[AOS09-P05] Impact of the astronomical lunar 18.6-yr tidal cycle on El-Niño and Southern Oscillation

*Ichiro Yasuda1 (1.Atmosphere and Ocean Research Institute, The University of Tokyo)

Keywords:El-Niño and Southern Oscillation, air-sea interaction, tide, mixing, climate

Even though El-Niño and Southern Oscillation (ENSO) has a tremendous impact on global climate and society, its long-term forecast remains difficult. In this study, we discovered a statistically significant relationship between ENSO timing and the 18.6-year period lunar tidal cycle in the mature-phase (December – February) ENSO time-series during 1867–2015 and extending back to 1706 with proxy data. It was found that El-Niño tended to occur in the 1st, 10th, and 13th years after the maximum diurnal tide in the 18.6-yr cycle, and La-Niña tended to occur in the 3rd, 12th, and 16th years. These tendencies were also confirmed by corresponding sea-surface temperature (SST) and sea-level pressure (SLP) distributions; particularly Pacific SST and SLP spatial patterns in the third La-Niña and the tenth El-Niño year well resemble those of Pacific Decadal Oscillation (PDO). These findings contribute to understanding and forecasting long-term ENSO variability.