Tides, Planetary Waves and Eddy Forcing
of the Mean MLT Circulation

The models to be employed include: (a) A steady-state linearized wave model (The Global-Scale Wave Model, or GSWM; height domain: 0 - 400 km) for climatological studies; (b) The Kyushu University GCM which has been extended into the thermosphere (height domain: 0 to 300 km); and (c) A nonlinear time-dependent spectral model (height domain: 0 - 300 km) to investigate interactions between large-scale waves and the mean flow, planetary-wave/tide interactions, and the role of gravity waves in the above processes. The science questions to be addressed are:

• What are the seasonal-latitudinal characteristics of the primary tidal and planetary wave (including Kelvin wave) oscillations in the 60 - 180 km height region ?
• How do the mean zonal and meridional circulations mutually interact with the above waves ? What are the implications on adiabatic heating/cooling rates and hence on the net thermal budget ?
• What role do gravity waves play in (1) and (2) ?
• How are the above effects manifested in minor species concentrations (i.e., O(3p), O(1s), CO2, OH) and in the various corresponding emissions to be measured by TIMED ?
  The scope of data analyses to be performed encompasses:

• Analysis of SABER temperatures to derive tidal and planetary wave variations in the temperature field and in the temperature variance field.
• Derivation of tidal and planetary wave variability in 5577 and 15 micron emissions, among others.
• Ground-based radar data to make aliasing assessments and to combine with space-based data to improve tidal and planetary wave determinations.
• Derivation of tidal and planetary wave fields from the TIDI wind and temperature data.