Validation of techniques for space based remote sensing of auroral precipitation and its ionospheric effects

Knowledge of the spatial distribution of auroral precipitation and its associated ionospheric effects is important both to scientific studies of the Earth's environment and successful operation of defense and communication systems. Observations with the best spatial and temporal coverage are obtained through remote sensing from space-based platforms. Various techniques have been used, including the detection of visible, ultraviolet and X-ray emissions produced by the precipitating particles. Interpretation of the measurements is enabled through theoretical modeling of the interaction of precipitating particles with atmospheric constituents. A great variety of auroral precipitation exists, with each kind differing in the type and energy distribution of the particles, as well as in its spatial and temporal behavior. Viable remote sensing techniques must be able to distinguish at least the species of particle, the total energy flux, and the average energy. Methods based on visible, ultraviolet and X-ray emissions meet these requirements to varying degrees. These techniques and the associated space instrumentation have evolved in parallel over the last two decades. Each of the methods has been tested using simultaneous measurements made by space-based imaging systems and ground-based measurements made by radars and optical instruments. These experiments have been extremely helpful in evaluating the performance and practicality of the instruments and the results have been crucial in improving instrument design for future remote sensing platforms. The next decade will see continued development and test of remote sensing instruments and the measurements, in addition to providing important operational data, will be increasingly more critical in addressing a number of scientific problems in auroral and atmospheric physics.