Open AccessMeridional circulation and the surface pressure change associated with the Southern Annular Mode: Comparison with the Arctic Oscillation
Author(s) -
Kuroda Yuhji
Publication year - 2005
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2005jd005860
Subject(s) - eddy , zonal and meridional , climatology , forcing (mathematics) , arctic oscillation , surface pressure , geology , geostrophic wind , circulation (fluid dynamics) , zonal flow (plasma) , oscillation (cell signaling) , atmospheric sciences , wavenumber , mechanics , physics , oceanography , turbulence , chemistry , biochemistry , plasma , quantum mechanics , northern hemisphere , tokamak , optics
Eddy forced meridional circulation and corresponding surface pressure change associated with the month‐to‐month variability of the Southern Annular Mode (SAM) are examined in the framework of the Eulerian mean dynamics, and they are compared with those of the Arctic Oscillation (AO). Effect of wave forcings on the surface pressure was diagnosed by means of a zonal mean quasi‐geostrophic model on the sphere. It is found that the surface pressure change associated with the SAM is mainly produced by the meridional circulation driven by mechanical and thermal eddy forcings of zonal wave number 1 and mechanical forcing by high‐frequency transient eddies. This contrasts with the surface pressure change associated with the AO, which is produced by the mechanical forcing by zonal wave number 2 or 3 and high‐frequency transient eddies. Close relationship between the meridional circulation and surface pressure was found not only for the month‐to‐month variability but also for the decadal variability as also observed for the AO.