Active Role of the ITCZ and WES Feedback in Hampering the Growth of the Expected Full-Fledged El Niño in 2014

• Maeda Shuhei

  Meteorological Research Institute

• Urabe Yusuke

  Japan Meteorological Agency

• Takemura Kazuto

  Japan Meteorological Agency

• Yasuda Tamaki

  Japan Meteorological Agency

• Tanimoto Youichi

  Faculty of Environmental Earth Science, and Graduate School of Environmental Science, Hokkaido University Application Laboratory, Japan Agency for Marine-Earth Science and Technology

Abstract

We investigated features of the atmosphere and ocean to seek a possible candidate that suppressed the growth of the El Niño event in 2014. In the boreal summer-fall season, equatorially antisymmetric sea surface temperature (SST) anomalies with a positive (negative) sign to the north (south) of the equator prevailed in the central and eastern tropical Pacific. In association with the SST anomalies, cumulus convective activity was enhanced in the region of the climatological Intertropical Convergence Zone (ITCZ). Anomalous southerly surface winds flowing across the equator toward the ITCZ induced upward latent heat flux anomalies and lowered SST in the near-equatorial region. These coherent spatial patterns between SST, wind, and latent heat flux anomalies suggested that the wind-evaporation-SST (WES) feedback sustained the suppression of the El Niño growth. A linear baroclinic model experiment indicated that the enhanced convective heating in the ITCZ also contributed to sustain the anomalous surface southerlies across the equator by the intense meridional atmospheric circulation over the equator. These results indicate that the anomalous southerlies across the equator sustained by the WES feedback and intense convective heating in the ITCZ contributed to the suppression of the El Niño growth.

Journal

• SOLA

  SOLA 12 (0), 17-21, 2016

  Meteorological Society of Japan

Keywords

• Atmospheric Science

Details

• CRID: 1390282680198686848
• NII Article ID: 130005125913
• DOI: 10.2151/sola.2016-004
• ISSN: 13496476
• Web Site: https://www.jstage.jst.go.jp/article/sola/12/0/12_2016-004/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed