HR: 0800h
AN: SA41A-1057    [Abstracts]
TI: Collaborative analysis of Planetary Waves in the Mesospheric Neutral Winds with SuperDARN and TIMED Observations
AU: * Ruohoniemi, J M
EM: mike_ruohoniemi@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins University, Laurel, MD 21042
AB: 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. The quasi 2-day planetary waves are prominent and their occurrence is seen to depend on season. By comparing the wave characteristics between the satellite and ground observations we obtain a complete breakdown of the wave activity in terms of wave periods and zonal wavenumbers. In addition, the semidiurnal tide is a ubiquitous feature of the mid-latitude mesosphere. A single radar station cannot resolve the sun-synchronous component from other contributions at the semidiurnal frequency. We show that with a chain of radars along a latitude band, the true sun-synchronous, or migrating, component can be inferred. Joint analysis can be performed chiefly with data from the SABRE and TIDI instruments.
DE: 3332 Mesospheric dynamics
DE: 3384 Waves and tides
DE: 2407 Auroral ionosphere (2704)
DE: 2494 Instruments and techniques
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting