Abstract. 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].

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A simple and accurate method is presented for the determination of lunar and solar harmonic terms present in a series of geomagnetic data. It is based on least-squares and incorporates a direct means for determining the confidence limits. The method is tested by applying it to a series of artificially generated data, and comparing the results both with the true answers and with results obtained using existing methods.

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