Impact of ENSO events on the interannual variability of Hadley circulation extents in boreal winter

Advances in Climate Change Research

Jian-Ping Li¹  Yi-Peng Guo² 

[1] College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China;State Key Laboratory of Numerical Modeling for Atmospheric Sciences, and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;

关键词: Hadley circulation;    Extents;    Meridional temperature gradient;    ENSO;   

DOI  :  10.1016/j.accre.2016.05.001

来源: DOAJ

【 摘 要 】

The interannual variability of the boreal winter Hadley circulation extents during the period of 1979–2014 and its links to El Niño-Southern Oscillation (ENSO) were investigated by using reanalysis datasets. Results showed that the El Niño (La Niña) events can induce the shrinking (expansion) of Hadley circulation extent in the Southern Hemisphere. For the Northern Hemisphere, El Niño (La Niña) mainly leads to shrinking (expansion) of the Hadley circulation extent in the middle and lower troposphere and expansion (shrinking) of the Hadley circulation extent in the upper troposphere. The ENSO associated meridional temperature gradients have close relationship with the Hadley circulation extents in both Hemispheres. But in the Northern Hemisphere, the ENSO associated eddy momentum flux divergence plays more important role in affecting the Hadley circulation extent than the meridional temperature gradient because of the small local Rossby number. In the Southern Hemisphere, as the ENSO induced eddy momentum flux divergence is small, the meridional temperature gradient dominates the change of the Hadley circulation extent.

【 授权许可】

Unknown