Abstract :
All satellite ion composition measurements available from satellites that traversed the low-latitude F-region can be combined into a common data set indexed to dip latitude, local time, longitude, time of year, and altitude, as well as geomagnetic and solar indices. Through binning, the data can be used to explore spatial variations of the most prominent F-region ion species. For the minor species of molecular ions O+2 and NO+ in the lower ionosphere, the available data are extensive enough to provide some snapshots of the average spatial morphology of the ion composition and variance through all phases of the solar cycle, but there are significant altitudinal gaps in data coverage when sorted on solar activity. This binned data set provides a useful tool to explore the low-latitude ionosphore. Examples are given of some binned data sorts demonstrating global trends, the appearance of ionospheric layers, and equatorial anomaly structures in the ensemble of measurements. The effect of chemical control of molecular ion concentrations is seen by the presence of latitudinal bulges in NO+ within the main F-layer, and scatter in the measurements provides evidence for latitude-dependent variability in the nightside ionosphere resulting from electrodynamic and instability processes.
