CONSEQUENCES OF CO2-O COLLISIONAL RELAXATION ON THE ENERGY BUDGET OF THE MESOSPHERE AND LOWER THERMOSPHERE

Recent increases in the accepted value of the CO2-O collisional relaxation rate to values in the range of 1-6 x 10(-12)cm(3)/sec have significant consequences for the energy budget of the mesosphere and lower thermosphere. First, as pointed out by several authors /1,2,3/, because of the increased CO2 cooling, a very low eddy diffusion coefficient is now required to balance the thermal budget. Second, the cooling/heating rate is nonlinearly dependent on the atomic oxygen mixing ratio thus rendering energy budget calculations more complicated. Finally, it appears that the atmosphere in this region is unstable to variations in the atomic oxygen mixing ratio and convection may occur. In this paper, these points will be elaborated upon, and the impact of horizontal inhogeneities in the concentrations of radiatively active constituents explored.