Collaborative analysis of Planetary Waves in the Mesospheric Neutral Winds with SuperDARN and TIMED Observations

The SuperDARN HF radars are best known for observing the ExB drift of ionospheric plasma in the high-latitude F region. At mesospheric altitudes the trails of ionization produced by meteors provide another kind of target for radar backscatter, and the motions imparted to these trails by winds in the neutral atmosphere can be measured. In the northern hemisphere the coverage of mesospheric winds currently extends over a 180 deg longitude sector but is confined by propagation conditions to latitudes near 55 deg geographic. We have analyzed several extended periods of simultaneous observations of the neutral wind involving SuperDARN and the TIMED suite of instruments. Often, the winds show clear evidence of large-scale wave events, including activity with periods of about 2 days. These planetary waves have large amplitudes, their occurrence depends on season, and they seem to recur. By comparing the wave characteristics between the satellite and ground observations we obtain a complete breakdown of the wave activity in terms of periods and zonal wavenumbers. In this presentation we demonstrate the coherence of the wave activity between the radar and satellite observations, describe the properties of the planetary waves, and discuss our findings on the spectra of the wave modes.