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

Abstract

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