Seasonal Variation of Solar Atmospheric Tides at Meteor Heights

Abstract

Systematic observation of the Kyoto meteor radar (35°N, 136°E) has been continuing since the end of 1977. A seasonal variation of diurnal and semidiurnal solar atmospheric tides at meteor heights has been studied by using meteor radar data. Monthly average behaviours of these tidal components have been summarized for the period from March 1979 to November 1980. Vertical profiles and harmonic dials of these components have been investigated in comparison with other meteor radar data. Complicated behaviour of diurnal tide can be explained by an interference between propagating and evanescent modes. The evanescent mode becomes dominant in summer, while the propagating mode appears in winter. As for semidiurnal tide, the S_{2, 2} mode is fundamental in summer, and the S_{2, 4} mode becomes apparent in winter.