Lunisolar Atmospheric Tides: A New Approach

Abstract

In records of the atmospheric pressure in Oslo, at 60' latitude, a one-day oscillation caused by the lunisolar tide has been detected. The amplitude has a mean value of O· 17 mb. This oscillation appears during intervals when the declination of the Moon has high numerical values. When the Moon passes through the equator, the one-day oscillation disappears and only the half-day mode continues. If a maximum coincides with upper culmination, it reappears during the next fortnight at lower culmination. This means that the phase changes approximately 180' or 12h every time the Moon crosses the equator, and this is the main reason why it has not been detected by means of traditional harmonic analysis of the atmospheric pressure oscillations. By means of the correlation between the pressure variation and the magnitude of the tidal acceleration, it was possible to separate the dynamic one-day oscillation from terms of thermal origin.