Interannual variations of North Equatorial Current transport in the Pacific Ocean during two types of El Niño

  • Guoli Wu (吴国丽)
  • Fangguo Zhai (翟方国)
  • Dunxin Hu (胡敦欣)
Physics
  • 106 Downloads

Abstract

Interannual variations of Pacific North Equatorial Current (NEC) transport during eastern-Pacific El Niños (EP-El Niños) and central-Pacific El Niños (CP-El Niños) are investigated by composite analysis with European Centre for Medium-Range Weather Forecast Ocean Analysis/Reanalysis System 3. During EP-El Niño, NEC transport shows significant positive anomalies from the developing to decay phases, with the largest anomalies around the mature phase. During CP-El Niño, however, the NEC transport only shows positive anomalies before the mature phase, with much weaker anomalies than those during EP-El Niño. The NEC transport variations are strongly associated with variations of the tropical gyre and wind forcing in the tropical North Pacific. During EP-El Niño, strong westerly wind anomalies and positive wind stress curl anomalies in the tropical North Pacific induce local upward Ekman pumping and westward-propagating upwelling Rossby waves in the ocean, lowering the sea surface height and generating a cyclonic gyre anomaly in the western tropical Pacific. During CP-El Niño, however, strength of the wind and associated Ekman pumping velocity are very weak. Negative sea surface height and cyclonic flow anomalies are slightly north of those during EP El Niño.

Keywords

North Equatorial Current transport interannual variation El Niño 

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Copyright information

© Chinese Society for Oceanology and Limnology, Science Press and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Guoli Wu (吴国丽)
    • 1
    • 2
    • 3
  • Fangguo Zhai (翟方国)
    • 4
  • Dunxin Hu (胡敦欣)
    • 1
  1. 1.Key Laboratory of Ocean Circulation and Waves, Institute of OceanologyChinese Academy of SciencesQingdaoChina
  2. 2.University of Chinese Academy of SciencesBeijingChina
  3. 3.College of ScienceChina University of PetroleumQingdaoChina
  4. 4.College of Oceanic and Atmospheric SciencesOcean University of ChinaQingdaoChina

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