GRAVITY WAVE-DRIVEN FLUCTUATIONS IN THE O2 ATMOSPHERIC (0-1) NIGHTGLOW FROM AN EXTENDED, DISSIPATIVE EMISSION REGION

The omission fluctuations of the O2 atmospheric (O2(b1SIGMA(g)+)) nigh tglow due to gravity waves, evanescent waves, and acoustic waves are c alculated using the Eulerian model formalism of Schubert et al. (1991) from which the complex parameter [eta] is derived: [eta] = ([I']/[IBA R])/([T(I)']/[T(I)BAR]) where I is the nightglow intensity, T(I) is in tensity-weighted temperature, the brackets denote an altitude intergra tion over all emitting layers, an overbar denotes an unperturbed state and a prime denotes a perturbation about the unperturbed state. The ( O2(b1SIGMA(g)+)) state is assumed to form directly by the three-body a ssociation reaction involving atomic oxygen (O + O + M - > O2(b1SIGMA( g)+) + M) and also via quenching of the intermediate state O2(c1SIGMA( u)-). Our calculated values of [eta] are compared with those derived f orm the observations of Zhang Initiative in Dynamics of the Atmosphere ) Act '89 campaign at Arecibo (18-degrees-N) during the period coverin g April 5 to May 9, 1989, were made with the MORTI (mesopause oxygen r otational temperature imager) instrument and provide us with values of both [eta] and the horizontal wavelengths of the gravity waves. For a ll of our results the undisturbed mesosphere is defined by the model o utput of Garcia and Solomon (1985) for a latitude of 18-degrees and fo r die months of March and June, these being most relevant to the obser vations of Zhang. For the evanescent waves, there is essentially good agreement between the theory and observations, while for the internal waves the agreement is best for \[eta]\. However, the comparatively la rger errors in the observed values of \[eta]\ make it impossible to de cide which chemical scheme used in the model provides die best results . The errors associated with the observed phases of [eta] are apparent ly minimal, and cannot account for the differences between the observe d and modeled phases of [eta]. The sensitivity of our modeled values o f [eta] to certain rate constants and the quenching parameters is inve stigated and discussed. In particular, we demonstrate that our modeled values of [eta] are sensitive to the quenching effects of atomic oxyg en and hence also to the production mechanism of the (O2(b1SIGMA(g)+)) .