Simulation of the influence of stationary planetary waves on the zonally averaged circulation of the mesosphere/lower thermosphere region

Abstract

A linearised numerical model has been used to simulate the stationary planetary waves (SPW) structure and investigate its influence on a zonally averaged circulation in the mesosphere and lower thermosphere. The wave-activity density. Eliassen-Palm flux, and its divergence cross-sections are used as a diagnostic of wave propagation and wave-mean flow interaction. The results of numerical simulations show that SPW can provide the substantial accelerations of the mean flow which are comparable with the accelerations due to the breakdown of internal gravity waves and atmospheric tides, and it is necessary to develop three-dimensional models of the general circulation of the lower thermosphere, taking account of the effects of gravity wave and tidal drag. The influence of the eddy thermal conduction and viscosity on the formation of SPW structure in the mesosphere and lower thermosphere and on the distribution of the mean flow accelerations due to SPW dissipation is discussed.