Advanced Modeling of the Ionosphere and Upper Atmosphere

Forecast skills of ionospheric operational models are negatively affected by the complexity of the underlying physical system and the necessity to specify a number of poorly known parameters. Hence these forecast models, including the PRISM used by the AirForce, are usually empirical, rather than the first-principles models. In addition, until recently ionospheric research suffered from lack and sparsity of observational data. This situation is changing dramatically owing mostly to advances in remotesensing of the ionosphere from space. Availability of vast amounts of observational data together with advances in computing power make it possible for the first time to apply data assimilation techniques to first-principles ionospheric models for improvedforecasting and modeling of the ionosphere and the upper atmosphere.The primary goal of this Phase I research proposal is to identify data assimilation methods most suitable for use with ionospheric models and to implement the prototype data assimilation and forecast system for spatial distribution and time evolution ofthe ionospheric electron density.In Phase I we plan to design and test the algorithms using the Coupled Thermosphere Ionosphere Model (CTIM). The developed data assimilation algorithms and codes would be applicable to any physics-based global ionospheric model. In Phase II of this effortwe will interface the developed system with the Coupled Thermosphere Ionosphere Plasmasphere Model (CTIPM) and the coupled thermosphere and ionosphere model CITFM used by the Air Force and create the practical real-time forecast system.Anticipated improvements in model's forecasts of ionospheric electron density profiles will be of immediate use for a number of military and civilian practical applications, particularly in communications and navigation.The proposed Phase I work will determine the fundamental data assimilation techniques needed to develop a practical operational electron density forecast system during the Phase II effort.In the private sector potential clients include companies operating cellular phone and pager networks, navigation infrastructure, in particular GPS receivers, other satellite-based communications, such as satellite-based wireless Internet serviceproviders, and power grid companies. Development of practically feasible ionospheric forecast system will address these needs and open up radically new commercial and military applications in the field of wireless communications.