A COMPARISON OF OBSERVED AND THEORETICAL DIURNAL TIDAL MOTIONS BETWEEN 30 AND 60 KILOMETERS

Abstract

Lindzen's theoretical predictions of the thermally driven diurnal tide are compared with observations of the diurnal amplitude and phase of the meridional wind component between 30 and 60 km for five groups of stations ranging in latitude from 64° N. to 8° S. In general, good agreement is found between theory and observation. The most important deviation occurs above 55 km where theoretical phases become progressively earlier than observed at lower latitude stations. This behavior suggests that the strength of the trapped modes in Lindzen's solutions is under-estimated relative to that of the propagating modes. Since the trapped modes are driven primarily by ozone heating in the upper troposphere and lower mesosphere, it is suggested that the problem of ozone heating requires further examination.