Coordinated Observations of 8- and 6-hr Tides in the Mesosphere and Lower Thermosphere by Three Meteor Radars Near 60°S Latitude

Atmospheric 8- and 6-hr tides are observed for the first time in the zonal and meridional winds at ~82–97 km altitudes simultaneously at Tierra del Fuego (TDF; 53.7°S, 67.7°W), King Edward Point (KEP; 54.3°S, 36.5°W), and Rothera (ROT; 67.5°S, 68.0°W) at Southern Hemisphere (SH) middle-to-high latitudes during long time spans, allowing to reveal climatology and migrating nature. The monthly averaged amplitudes vary between ~1 and 8 m/s for the 8-hr tides while the amplitudes of 6-hr tides are smaller ~0.5–4 m/s. Both tides exhibit an annual pattern having the amplitude maxima during SH winter and minima in SH summer. The tidal phases are smaller (earlier) in the zonal wind than in the meridional wind by about 90°. The phase differences observed between TDF and KEP, which are located at similar latitudes but different longitudes suggest the propagation of migrating tides. The study finds that 8- and 6-hr tides are correlated.