An extensive survey is made of the equatorial occurrences of the metallic ion Fe+ as detected by the ion mass spectrometer on the equatorial orbiting satellite Atmosphere Explorer E. It considers the longest time period (4 years) data base available for the study of the equatorial metallic ion distributions. The distributions of the Fe+ ions are explored through the use of percentages of occurrences within spatial and temporal windows of the independent variables: dip latitude, local time, altitude, longitude, and season. Concentrations of the metallic ions exceeding 10, 30, and 100 cm-3 were considered. The number of occurrences in the F region were most frequent at the dayside dip equator. Diurnally, the events were not appreciable in the F region until a few hours after dawn, reaching a maximum near noon followed by a secondary maximum in the afternoon. Near and after dusk the Fe+ ions extended on the average to higher altitudes than during the day and became less and less frequent from midnight to dawn. Seasonally, the distributions between 200 and 300 km were skewed away from the dip equator during the day with the maximum frequency of occurrence north (south) of the dip equator during a period centered on the December (June) solstice; the average nighttime distributions did not have the opposite seasonal relationship. No correlation was evident at all between any features of the frequency of the F region events and meteoritic input variations. There was evidence for a spreading of the events in latitude with increasing altitude. Theoretical studies of the dynamical evolution of the equatorial metallic ion distributions thus far published do not account for some of the observed features. ¿ American Geophysical Union 1989 |