On the Maintenance of Stationary Eddies in Terms of the Streamfunction Budget Analysis

Tsing-Chang Chen Atmospheric Science Program, Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa

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Jau-Ming Chen Atmospheric Science Program, Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa

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Abstract

The upper-level seasonal-mean eddy streamfunction (ψ̄E) is often used to portray atmospheric stationary eddies. A budget analysis of the 200 mb ψ̄E field simulated by the NCAR Community Climate Model revealed that a quadrature relationship exists between ψ̄E and the ψ̄E tendency induced by either the vorticity advection associated with rotational flow (χ̄ψ) or by the vorticity source with divergent flow (χ̄D); that χ̄ψ and χ̄D counterbalance each other to a large extent; and that physical processes not included in χ̄ψ and χ̄D are generally insignificant, as can be inferred from the residual between χ̄ψ and χ̄D. Apparently, ψ̄E is maintained primarily by the counterbalance between χ̄ψ and χ̄D. To better illuminate the aforementioned quadrature relationship it must be explained that the ψ̄E budget was formulated explicitly with zonal and eddy flow components. The detailed ψ̄E budget analysis indicated that the distinct low- and high-latitude ψ̄E regimes am maintained in different manners.

Abstract

The upper-level seasonal-mean eddy streamfunction (ψ̄E) is often used to portray atmospheric stationary eddies. A budget analysis of the 200 mb ψ̄E field simulated by the NCAR Community Climate Model revealed that a quadrature relationship exists between ψ̄E and the ψ̄E tendency induced by either the vorticity advection associated with rotational flow (χ̄ψ) or by the vorticity source with divergent flow (χ̄D); that χ̄ψ and χ̄D counterbalance each other to a large extent; and that physical processes not included in χ̄ψ and χ̄D are generally insignificant, as can be inferred from the residual between χ̄ψ and χ̄D. Apparently, ψ̄E is maintained primarily by the counterbalance between χ̄ψ and χ̄D. To better illuminate the aforementioned quadrature relationship it must be explained that the ψ̄E budget was formulated explicitly with zonal and eddy flow components. The detailed ψ̄E budget analysis indicated that the distinct low- and high-latitude ψ̄E regimes am maintained in different manners.

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