Multiplicity and stability of solutions for a simple Chapman and a more complex mesospheric photochemical model

The goal of this article is to examine the validity of some properties of p hotochemical models, a which were found numerically in recent studies: (1) the existence of periodic solutions and (2) the stability of these solution s. Even. though we are interested in a more complete mesospheric model. nle examine first; the simple Chapman model and then we generalize the results to the complete one. We show: that the 48-hours periodic solution found in earlier work is orbitally stable, thus enhancing its physical significance . On the other hand, we find tno new 24-hours periodic solutions, which pre sent ozone concentrations at much lower levels relative to the experimental data.