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Baroclinic wave packets in an extended quasigeostrophic two‐layer model
Author(s) -
Yang Wenchang,
Nie Ji,
Lin Pu,
Tan Benkui
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl029077
Subject(s) - baroclinity , wave packet , asymmetry , physics , amplitude , zonal flow (plasma) , mean flow , perturbation (astronomy) , geology , mixed layer , nonlinear system , jet (fluid) , mechanics , geophysics , meteorology , turbulence , atomic physics , quantum mechanics , plasma , tokamak
An extended quasigeostrophic two‐layer model including nonlinear Ekman pumping and nonlinear interface perturbation is used to numerically study the formation and maintenance of baroclinic wave packets. With an initial zonal jet flow of north–south symmetry and small random initial perturbations wave packets of finite amplitude are produced and maintained with an equilibrated wave packet‐zonal flow system exhibiting simultaneously downstream‐upstream asymmetry and north–south asymmetry, the later of which has not been observed in the past simple quasigeostrophic two‐layer modeling studies. The northern upstream part of the wave packets is stronger than its southern upstream counterpart and therefore the peak of time‐and‐zonal‐average eddy kinetic energy associated with the wave packets is shifted poleward while the peak of the time‐mean zonal jet flow is shifted equatorward, which is in agreement with the observations.