More than 40 rocket flights through the main meteoric ionization layer, which peaks near 95 km, have sampled the meteoric metallic ion concentrations.
Five of these flights were conducted during or near the peak times of a meteor shower. In each of the latter studies the observed meteoric ion concentrations were assumed to be a consequence of the shower. These measurements were not complemented by baseline observations made for similar ionospheric conditions immediately before the shower and no rigorous quantitative comparisons were made using average non-shower distributions. In order to further investigate the impact of the shower on the ionosphere, all published ion concentration altitude profiles obtained from sounding rockets in the meteoric ionization regime have been scanned to develop a digital data base of meteoric ion concentrations.
These data are used to provide the first empirical altitude profile of the metallic ions. The average observed Mg+ concentrations are lower than those yielded by the most comprehensive model to date (McNeil et al., 1996). This compiled ensemble of data provides supporting evidence that meteor showers do have a significant impact on the average ionosphere composition.
Although there is much variability in the observed meteoric layers, the peaks in the total metallic ion concentrations at mid-latitudes, on the dayside, observed during meteor showers had concentrations comparable to, or exceeding, the highest concentrations measured in the same altitude regions during non-shower periods.