Open AccessBaroclinic Instability in the Eady Model: Interpretations
Author(s) -
Joseph Egger
Publication year - 2009
Publication title -
journal of the atmospheric sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.853
H-Index - 173
eISSN - 1520-0469
pISSN - 0022-4928
DOI - 10.1175/2008jas3014.1
Subject(s) - baroclinity , barotropic fluid , instability , advection , mode (computer interface) , stream function , physics , flow (mathematics) , zonal flow (plasma) , geology , mechanics , climatology , classical mechanics , computer science , thermodynamics , plasma , vortex , vorticity , quantum mechanics , tokamak , operating system
The mechanism of baroclinic instability in the Eady model is interpreted by explicitly calculating the ageostrophic circulations related to the model’s hyperbolic basic functions. It is advantageous to perform the analysis at the midlevel where the model’s “barotropic” mode provides the streamfunction and the “baroclinic” mode represents the temperature. These modes interact and instability occurs if the horizontal advection of background potential temperature by the barotropic mode dominates over the vertical one because of the same mode at the midlevel. A rather simple picture of the stable as well as the unstable flow configurations emerges. Other interpretations are discussed briefly.