Creation of a Zonally Symmetric Tide due to the Interference of the Migrating Diurnal Tide and a Quasi-Stationary Wave

摘要

An investigation was conducted into the effect of the interference of the migrating diurnal tide and a quasi-stationary wave of zonal wavenumber 1 to produce a zonally symmetric diurnal tide, making use of a general circulation model. It was found that the new zonally symmetric tide is created at the upper stratosphere in the winter hemisphere when the quasi-stationary wave amplifies. The amplitude of the new tide was found to be comparable to or larger than that of the tide propagating from the surface. This creation is expected to occur when the forced Rossby waves of zonal wavenumber 1 have large amplitude and the polar night jet-shift or warming event occurs.