Advances in Atmospheric Sciences

, Volume 30, Issue 6, pp 1732–1742

Impacts of two types of El Niño on atmospheric circulation in the Southern Hemisphere

  • Dan Sun (孙 丹)
  • Feng Xue (薛 峰)
  • Tianjun Zhou (周天军)
Article

DOI: 10.1007/s00376-013-2287-9

Cite this article as:
Sun, D., Xue, F. & Zhou, T. Adv. Atmos. Sci. (2013) 30: 1732. doi:10.1007/s00376-013-2287-9

Abstract

Based on NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalysis data from 1979 to 2010, the impacts of two types of El Niño on atmospheric circulation in the Southern Hemisphere (SH) are analyzed. It is shown that, when a warming event occurs in the equatorial eastern Pacific (EP El Niño), there is a negative sea level pressure (SLP) anomaly in the eastern Pacific and a positive one in the western Pacific. Besides, there exists a negative anomaly between 40°S and 60°S and a positive anomaly to the south of 60°S. When a warming event in the central Pacific (CP El Niño) occurs, there appears a negative SLP anomaly in the central Pacific and a positive SLP anomaly in the eastern and western Pacific, but the SLP anomalies are not so evident in the SH extratropics. In particular, the Pacific-South America (PSA) pattern induced by the CP El Niño is located more northwestward, with a weaker anomaly compared with the EP El Niño. This difference is directly related with the different position of heating centers associated with the two types of El Niño events. Because the SST anomaly associated with CP El Niño is located more westward than that associated with EP El Niño, the related heating center tends to move westward and the response of SH atmospheric circulation to the tropical heating changes accordingly, thus exciting a different position of the PSA pattern. It is also noted that the local meridional cell plays a role in the SH high latitudes during EP El Niño. The anomalous ascending motion due to the enhancement of convection over the eastern Pacific leads to an enhancement of the local Hadley cell and the meridional cell in the middle and high latitudes, which in turn induces an anomalous descending motion and the related positive anomaly of geopotential height over the Amundsen-Bellingshausen Sea.

Key words

eastern Pacific El Niñocentral Pacific El Niñoatmospheric circulationSouthern HemispherePacific-South America pattern

Copyright information

© Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Dan Sun (孙 丹)
    • 1
    • 2
  • Feng Xue (薛 峰)
    • 1
  • Tianjun Zhou (周天军)
    • 1
  1. 1.State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina
  2. 2.Beijing Meteorological BureauBeijingChina