THE COUPLED IONOSPHERE AND THERMOSPHERE AT MIDLATITUDES IN THE ASIAN SECTOR AND ITS COMPARISON WITH OTHER LOCATIONS

The present paper reviews dynamical features of the mid-latitude ionos phere and thermosphere in the Asian sector as quantified by the MU rad ar at Shigaraki, Japan (35 degrees N, 136 degrees E) and compares thes e with dynamics reported for other locations. The thermospheric wind a nd temperature in the Asian sector differ from the wind and temperatur e measured at other mid-latitude locations. Furthermore, the perpendic ular plasma drifts have strong resemblances to those predicted by curr ent models, but their seasonal trends suggest a strong conjugate effec t that has not been fully incorporated into our expectations of local behavior. These results provide additional evidence that global featur es cannot be described by a simple zonal mean. Finally, mio features r elated to gravity waves are discussed. Gravity waves seem to be ubiqui tous in the thermosphere and play an important role in creating a vari ety of electron density fluctuations and irregularities in the mid-lat itude ionosphere. Tracking the progression of ionospheric gravity-wave effects between MU radar beams has allowed gravity wave packets to be identified and their dispersion relation to be determined. The charac ter of ionospheric irregularities observed are consistent with their s eeding by the Perkins mechanism.