OBSERVATIONS OF IONOSPHERICS ELECTRIC-FIELDS ABOVE ATMOSPHERIC WEATHER SYSTEMS

We report on the observations of a number of quasi-dc electric field e vents associated with large-scale atmospheric weather formations. The observations were made by the electric field experiment onboard the Sa n Marco D satellite, operational in an equatorial orbit from May to De cember 1988. Several theoretical studies suggest that electric fields generated by thunderstorms are present at high altitudes in the ionosp here. In spite of such favorable predictions, weather-related events a re not often observed since they are relatively weak. We shall report here on a set of likely E field candidates for atmosphere-ionosphere c ausality, these being observed over the Indonesian Basin, northern Sou th America, and the west coast of Africa; all known sites of atmospher ic activity. As we shall demonstrate, individual events can often be t raced to specific active weather features. For example, a number of ev ents were associated with spacecraft passages near Hurricane Joan in m id-October 1988. As a statistical set, the events appear to coincide w ith the most active regions of atmospheric weather.