With the advent of the era of thermosphere/ionosphere weather modeling there is an increasing need to routinely acquire information on important regional-scale phenomena in the upper atmosphere like atmospheric gravity waves (AGWs) in the thermosphere and their ionospheric signatures, the traveling ionospheric disturbances (TIDs). AGW information is especially desirable in view of its role in the momentum and energy balance of the upper atmosphere. Measuring AGWs directly is difficult, however, so they are usually traced by the TIDs, which can be routinely observed by the powerful incoherent-scatter technique even in all fundamental ionospheric parameters. Thus an important problem, and the central concern of this study, is how to infer, as comprehensively as possible, AGW information from measured TIDs. This problem was tackled up to now by direct inversion of TID parameters into AGW parameters, but severe limitations, which we shall briefly discuss, are inherent in this approach. Contrasting with this, we introduce a novel approach to AGW retrieval: realistic modeling of AGW/TID physics, constrained by TIDs measured by the incoherent-scatter technique.

This method is found to be capable of yielding comprehensive AGW information, that is, the full polarization and dispersion information. We applied the method to four TID events, which cover different seasons and solar activities during quiet magnetic conditions, from European EISCAT radar data. One-to-one comparisons of modeling results with experimental data are presented and discussed. These show the feasibility and scope of the method and its potential to discriminate between TIDs from AGWs and non-AGW sources. In view of the satisfactory results, we finally address the potential of the method for routine processing of incoherent-scatter data with respect to AGWs, which could provide valuable AGW information for other research. ¿ American Geophysical Union 1995