Introduction:

At this website, we present recent model results that illustrate the thermal, compositional and dynamical responses of these upper atmospheres to solar EUV-UV flux variability making use of the Earth TIEGCM, the Mars MTGCM, and the Venus VTGCM three-dimensional models. Each of these models has been developed and exercised at the National Center for Atmospheric Research using its CRAY computers. The motivation of this research is not only to simulate the observed responses of these individual planets to solar EUV-UV flux variations, but also to understand the relative importance of common processes that regulate this unique behavior. For instance, the role of O-CO2 enchanced 15-micron cooling (thermostatic effect) is investigated in the context of global dynamics and its effect on atomic-O distributions. In addition, the role of global dynamics in controlling temperature distributions (and their variations over the solar cycle) is studied. Standard EUV-UV solar flux datasets are adopted for use in all three thermospheric models. Specific cases for solar maximum (MAX) (F107=200), solar medium (MED) (F107=130), and solar minimum (MIN) (F107=68) conditions are conducted. Corresponding figures for each planet are displayed horizontally (in 3-panels) so that steady state output fields can be easily compared. In addition, time dependent (solar flux) runs are also conducted for each planet in order to monitor the timescales for equilibration among the changing composition, temperature, and wind fields. These timescales are clearly a strong function of altitude and therefore are quite different for each planet as a result of the feedbacks and thermostats in operation for each. Corresponding time-dependent figures are again displayed horizontally (in 3 panels) to aid comparison.