The morphology of metallic ions in the upper atmosphere

The metallic ion data from a day‐night pair of rockets, from Ogo 6, and from the elliptic phases of AE‐C and AE‐D have been examined for their morphological implications. The high altitude (>400 km) nighttime data from Ogo 6 show Fe + ions only at low (<30°) magnetic latitudes. The detection probability of Fe + decreases with altitude, is maximum over the Atlantic and minimum over India, and appears to be influenced by zonal winds. The rocket data show ions in the E region during the day and on the bottom of the F layer at night, as might be expected from the influence of global winds. Metal ions are observed below 250 km at all latitudes and local times by the Atmosphere Explorer satellites. There is a high spatial correlation in the appearance of the different metallic ions. Mg + and Fe + are the dominant ions, but Al + , Na + , Si + , and Ca + are very often detectable. The Atmosphere Explorer data also reveal the presence of these ions in the topside ionosphere near the daytime equator and at midlatitudes during summer mornings. At high latitudes metal ions show a preference for afternoon over morning that is probably caused by global winds and large scale ion convection. There appears to be a strong positive correlation between solar activity and the metallic ion detection probability at low latitudes and high altitudes at night.