On the asymmetric diurnal tide

Summary The response of the atmosphere to a diurnally oscillating thermal drive, asymmetric with respect to the equator, is investigated. It is found that the solutions ofLaplace's tidal equation do not form a complete set; all of them being orthogonal to the associated Legendre polynomial,P₂¹(cos ), being the latitude. As an extension ofLaplace's theorem for gravitationally excited ocean tides to thermally driven atmospheric tides, it is shown that a diurnal drive whose latitude dependence is given byP₂¹ gives rise to no surface pressure oscillation.