Lunar tidal winds in the upper atmosphere over Jakarta

Abstract

Winds have been measured at heights from 70 to 120 km by means of a Meteor Wind Radar near Jakarta (6.4S, 106.7E) from 1993 to 1997. These data have been analysed for the lunar semidiurnal tide using a least squares fitting method. Generally lunar tidal amplitudes in the winds are about 2 m s−1 though the northward wind amplitude reaches 6 m s−1 in southern summer. Variations with height and season are shown and compared with the Global Scale Wave Model (GSWM). Often the agreement with the model is good but there is a difference in phase of the eastward wind in southern winter. The GSWM predicts a more rapid increase in northward wind magnitude with height than is observed. Year‐to‐year changes are examined for different seasons and these reveal sometimes consistent results and sometimes a variation in phase from year to year. Often the phase relations between eastward and northward winds at Jakarta are more characteristic of a Northern Hemisphere tide, as predicted by classical tidal theory, particularly in southern spring and summer.