Coupling phases and amplitudes of minor constituents with temperature perturbations in the lower thermosphere

Abstract. Based on the linearized theory of atmospheric gravity waves (AGW) and considering the effects of temperature perturbation on the chemical rate coefficients, the formulae of coupling relations between nj/n_j and T'/T driven by AGW (n_j and T denote the background quantities) are described, the coupling phases and amplitudes of minor constituents O₃, NO, H, OH, and O are analyzed in detail for the mesopause (86 km) and just upside of the O layer (100 km) at daytime. A general principle is outlined: the coupling phases are strongly dependent on density scale heights and perturbation scales, while the amplitudes are little affected by these two factors. A criterion to distinguish the coupling behaviour is given: when the minor constituent number density scale height H_j satisfies 1-γH_m/H_j>0 (H_m denotes the scale height of the major constituent), the dynamical perturbation process always keeps the nj/n_j in phase with T'/T, i.e. keeps the nj/n_j in antiphase with that of the major constituent. The results obtained indicate that both the temperature dependence of reaction rate coefficients and the profile slopes of the O distribution may have a major influence on the behaviour of the coupling relations.