Lunar tides in the mesosphere over Christmas Island (2°N, 203°E)

This paper reports the first measurement of the lunar tide in upper atmosphere winds at an equatorial site. Wind velocities have been measured at Christmas Island, in the Pacific Ocean, from 1990 to 1993 over the height range 82 to 98 km and hourly values have been used to deduce the lunar tide using a least squares method. Amplitudes are 1 to 3 m/s with only small changes in phase with season. A large phase change over the early part of 1990 was found in the northward wind. Generally, the phase difference between northward and eastward winds was about 6 hours, and good agreement was obtained with a tidal model developed from that of Forbes [1982a].