Past studies of global changes in the middle atmosphere have predicted dramatic changes in thermal regime, structure, and composition with doubled carbon dioxide. The PI responds to these preliminary findings by examining the thermal and dynamical response to doubling carbon dioxide in the mesosphere and lower thermosphere (MLT), using a three-dimensional Spectral Mesosphere/Lower Thermosphere Model. Recently extended into the thermosphere and tested on empirical climatologies, the model is applied to a wide range of carbon dioxide concentrations through a parameterization of infrared radiative transfer for the middle and upper atmosphere. The PI also modifies this model to account for radiative, dynamical, and chemical feedback important for MLT global change studies. Because of the associated thermal contraction of the upper atmosphere, data gathered from the research can eventually be applied to the revision of life time and trajectory calculations of orbiting and re-entry space vehicles.
