Equatorial anomaly variability as a function of the local time and the longitude

The equatorial anomaly dynamics is very difficult to study due to necessity of its monitoring in space (latitude-longitude) and local time simultaneously. This task is impossible for the single-point measurements, and only the satellite technology may help. The present paper is devoted to the preliminary analysis of the equatorial anomaly dynamics combining two techniques - the topside sounding and GPS TEC measurements. The topside sounding gives the unique opportunity to build the global structure of the equatorial anomaly for the fixed local time (LT-maps) and to reveal the longitudinal variations, while the chains of GPS receivers along the meridian permit to study the latitudinal variations of TEC in local time. Two meridional chains of GPS receivers were selected: at 115 deg. E and 70 deg. W longitudes. Combining of two technologies makes it possible to obtain three-dimensional global dynamics of the equatorial anomaly. The paper demonstrates the power of the technique itself while the more detailed and comprehensive analysis will be continued in the following papers.