Magnetic storm associated perturbations of the upper atmosphere: Recent results obtained by satellite‐borne gas analyzers

Abstract

This review summarizes some of the recent results on the disturbed upper atmosphere obtained by satellite‐borne gas analyzers. According to these measurements, magnetospheric activity leads to the development of two different disturbance zones. The high‐ and middle‐latitude region is characterized by an increase in the heavier constituents Ar, N2, and O2, by a height‐dependent behavior of O, and by a significant decrease of He. The reaction time of the atmosphere is much smaller than one orbital period. At lower latitudes a moderate increase of all constituents is observed. A comparison between atmospheric and ionospheric data demonstrates that, in contrast to positive effects, negative ionospheric storms are closely coupled to changes in the neutral composition. In addition, model calculations fully support a causal relation between both phenomena. Given this correlation, atmospheric and negative ionospheric disturbance effects have certain variations in common. These include systematic changes with the magnetic storm intensity, with magnetic position, with local time, and with season. Whereas the presently available empirical and theoretical models are quite capable of reproducing the basic properties of the observed atmospheric perturbations, these algorithms are not sophisticated enough for a more detailed description of the data.