Note on a supposed determination of the lunar diurnal tide in the ionosphere

Since Newton founded and Laplace developed the gravitational theory of the tides, the somewhat concealed tidal influence on the atmosphere, as well as the obvious oceanic tide, has been much studied [2]. Later these studies were extended to the ionosphere, first by Appleton and Weekes [3]. Hitherto only the semidiurnal lunar tide has been found in the atmosphere; the diurnal tide predicted by theory, reversed fortnightly when the moon crosses the equator, has never yet been detected in meteorological data; all claims to have done so have proved fallacious. In the ionosphere the semidiurnal tide is far larger than the oceanic or lower-atmospheric tides; hence the hope of detecting the lunar diurnal tide is brighter there than elsewhere. The purpose of this note is to show, however, that a recent announcement by Jones and Jones [4] of its detection in the F layer at College, Alaska, is not well-founded; this does not imply that it may not exist there and be determinable.