First meteor radar observations of tidal oscillations over Jicamarca (11.95° S, 76.87° W)

Abstract

Tidal oscillations in the equatorial mesosphere and lower thermosphere (MLT) region over Jicamarca (11.95° S, 76.87° W) are studied using the observations from the newly installed Jicamarca All-sky Specular MEteor Radar (JASMET). The vertical structure and seasonal variability of diurnal and semidiurnal tides from 80-100 km are presented. The analyses show a strong diurnal tide over Jicamarca for both zonal and meridional components with the meridional amplitudes being larger than the zonal ones. Maximal diurnal amplitudes, 45 m/s for zonal and 55 m/s for meridional, are observed around equinox. The zonal diurnal amplitudes reach maxima at 90-96 km, while the meridional diurnal amplitudes grow with altitude for most months. Semidiurnal amplitudes vary not as strong as diurnal amplitudes. The vertical structures of the tidal components are compared with Global Scale Wave Model (GSWM02) prediction and the tidal wind analysis results from TIDI measurements onboard of the TIMED satellite. The data from JASMET and TIDI show similar amplitudes for both diurnal and semidiurnal tides. GSWM02 overestimates diurnal amplitudes, but underestimates semidiurnal amplitudes for both zonal and meridional components.