The integrated ionospheric response to internal atmospheric gravity waves

Abstract

The effect of internal atmospheric gravity waves upon columnar electron content is studied using a model consisting of plane internal gravity waves propagating in a viscous atmosphere composed of a number of isothermal layers and a description of the wave-ionization interaction which includes the effects of the wave upon diffusion, photoionization and losses. Attention is restricted to columnar electron content obtained using transmissions from geostationary satellites. The geometry of the problem is then determined by the geomagnetic latitude of the observing location and the longitudinal separation between observer and satellite. The effect of variations in these quantities upon the integrated response to the waves is studied as a function of wave azimuth for various waves. The response obtained is quite dependent upon the wave parameters and the geometry of the observing situation. However, under certain circumstances, the integrated response to larger-scale waves behaves similarly to the response of the electron concentration at a single height. Some suggestions for the use of electron content measurements for the study of atmospheric gravity waves are outlined. Since the accuracy of the determination of the perturbations in electron content is limited almost entirely by the accuracy of the description of the perturbations in the electron concentration at all heights, considerable attention is paid to the problem of the effect of the waves upon the electron concentration. Inclusion of wave-induced perturbations in diffusion and loss are important for the situations studied, while perturbations in photoionization are relatively unimportant. The response of the electron concentration below 200 km is very sensitive to the loss rates used.