The notion that 11-year solar cycle induced changes in the index of refraction (IOF) of the planetary waves can affect the large-scale circulation and climate has been circulating in the scientific literature for more than 30 years. This so-called IOF theory hinges on solar cycle induced ozone changes directly affecting the zonal-mean temperature field, which, through thermal wind balance, changes the zonal-mean wind field. However, the IOF theory, as traditionally cited, does not form a complete picture. In reality, the IOF can also change due to the diabatic heating perturbations generated by the interactions between the planetary waves and the zonal-mean ozone field, an important point that has been overlooked in previous studies.
With the importance of wave-ozone feedbacks in mind, we consider a model atmosphere that is governed by coupled equations for quasigeostrophic potential vorticity and ozone volume mixing ratio. A WKB analysis yields an analytical expression that shows, for the first time, how solar cycle induced changes in the stratospheric ozone field can affect the IOFs, reflection coefficients and tropospheric amplitudes of the forced planetary waves. The analytical results, which are confirmed numerically, show that the tropospheric response to solar cycle induced perturbations is sensitive to the height of the stratospheric reflecting surface, which is a strong function of the zonal-mean wind, temperature and ozone fields.