Photochemical-Dynamical Modeling of the Measured Response of Airglow to GravityWaves. 1: Basic Model for OH Airglow

摘要

A photochemical-dynamical model for the OH Meinel airglow is developed and usedto study the fluctuations in OH emission due to atmospheric gravity waves propagating through the mesosphere. The linear response of the OH Meinel emission to gravity wave perturbations is calculated assuming realistic photochemistry and gravity wave dynamics satisfying Hines (1960) isothermal windless model. Two types of correction terms to the latter class of models are found, one involving advection of excited-state populations by the gravity wave and one involving quenching of OH(v) by collisions with perturber molecules. Effects of these additional terms are expressed in terms of the so-called Krassovsky ratio eta, which relates relative fluctuations in the column intensity measured by a passive optical instrument to relative fluctuations in the ambient temperature. The extra wave advection term is found to be unimportant under typical conditions, but quenching is important and has two major effects: (1) It makes eta a vibrational-level-dependent quantity, and (2) it can lower eta by more than 50% depending on the wave period. jg p1.