A dynamical‐chemical model of tidally driven fluctuations in the OH nightglow

Abstract

A theory is presented to explain tidally induced oscillations in the emission intensity I and rotational temperature T of the OH nightglow. The theory includes photochemical reactions among H, O, O 3, OH, and HO 2 and the complete dynamics of tides in an isothermal, uniformly rotating atmosphere. The ratio rl = (6I/[)/(6T/T) (6 refers to a perturbation quantity and the overbar signifies an average) depends on basic state atmospheric structure, minor constituent scale heights, especially that of O, and altitude of OH emission. For both semidiurnal and diurnal migrating modes, r/ has an amplitude in the approximate range 1-2.5 and a phase between about 10 ø and 30 ø.

Airglow variability in the context of the global mesospheric circulation

“…This is now called the Krassovsky ratio, a complex quantity that incorporates the observed phase shift between the two observables. Krassovsky's formulation was recast by Hines and Tarasick (1987) and has been studied by many others, including Walterscheid and Schubert (1987) and more recently Liu and Swenson (2003). Although short-period variations are not part of the current study, they do fit into the overall pattern described.…”

Dynamics of the Earth's Thermosphere: A Review

“…Recently Walterscheid et al [1987] described the results of a detailed dynamical‐chemical model of wave‐driven OH nightglow fluctuations. Tidal effects were considered by Walterscheid and Schubert [1987].…”

Multiyear observations of tidal oscillations in OH M(3,1) rotational temperatures at South Pole, Antarctica

“…The wavefield at the upper mesospheric and the lower thermospheric (MLT) altitudes represents mainly a mixture of gravity waves, tides, and planetary waves [ Forbes , 1985; Hickey et al , 1992; Sivjee et al , 1994]. These waves modulate MLT density and temperature and lead to variations in the brightness ( B ) and the temperature ( T ) of the airglow emissions originating in the MLT region [ Hickey et al , 1992; Walterscheid and Schubert , 1987, 1995]. Thus, ground‐based observations of airglow B and T provide a measure of the effects of disturbances in the MLT region [ Sivjee and Hamwey , 1987; Sivjee et al , 1987].…”