Linear stationary wave simulations of the time-mean climatological flow

Abstract

A spectral, σ-coordinate model linearized about a zonal mean flow is used to investigate the maintenance of the December-February climatological stationary waves. The model is generally run with 15 levels in the vertical and a T31 truncation. Orographic features, tropical and midlatitude heating and transient vorticity and heat flux convergences are shown to be significant. In particular, orography accounts for approximately 30% of the total 200 mb planetary wave response. In midlatitudes the diabatic heating maxima in the two storm tracks are important. This heating is related to latent and sensible heating associated with transient disturbances. The explicit transient eddy terms in the vorticity and thermodynamic equations force a complicated upper-level flow pattern. -from Authors