Ionospheric climate and weather modeling

The ionosphere is typically defined to be that part of Earth's upper atmosphere in hich the concentration of free electrons and ions is sufficient to affect the propagation of radio waves. It begins at an altitude of ∼70 km and extends to roughly 3000 km, with the peak electron concentration occurring at approximately 300 km (F region). Although the existence o f the ionosphere was first suggested in the late 1800s to explain certain geomagnetic phenomena, it was not until 1901, when G. Marconi successfully transmitted radio signals across the Atlantic Ocean, that its presence was clearly established. Since that time, the ionosphere has been studied extensively with the aid of ionosondes, radars, rockets, satellites, the space shuttle, and numerical models, and the knowledge gained about its behavior has increased to the point where the development of predictive ionospheric models can begin.