A REDUCED MODEL FOR COMPLEX OSCILLATORY RESPONSES IN THE MESOSPHERE

A kinetic model for chemical reactions in the mesosphere, previously s hown to support simple and complex oscillatory responses, is examined. The underlying chemical origins of the change between different oscil latory responses is rationalised in terms of the evolution of the conc entrations of the HOx species. Mechanism and variable reduction method s are employed to produce a 12 reaction scheme with two dynamic variab le concentrations ([H] and [O], with [OH], [HO2] and [O-3] treated thr ough the dynamic steady-state approximation). The reduced model is use d to investigate the effect of species transport longitudinally. The l atter shows that complex responses can still arise, but that high tran sport rates eventually lead to a synchronous state in which the concen trations of the species become effectively constant in space and time.