GPS radio occultation data use in operational ionospheric models

Global Positioning System (GPS) Radio Occultation (GPSRO) data are currently available for space weather operations from the Constellation Observing System for Meteorology (COSMIC) satellite constellation. This dataset, which currently is used in tropospheric and stratospheric models, shows promise as a primary feed into ionospheric models. As the space weather community goes forward with initiatives to gather and provide additional GPSRO data from various platforms, exploitation of these observations becomes an important factor in the specific steps to update models (such as Global Assimilation of Ionospheric Measurements (GAIM) model from Utah State University (USU)) and to enable full integration in operations.

Radio Occultation uses the precise measurement of phase delay and amplitude of GPS signals to deduce atmospheric properties. GPSRO from the six COSMIC satellites provides all-weather global coverage with around 2500 high-quality ionospheric measurements per day.

Ionospheric models have been demonstrated to decline in accuracy over oceans and other locations remote from ionospheric observations. Most traditional ionospheric sensors are ground-based and observations available for real-time use have been mostly limited to the major continental land masses. GPSRO has been demonstrated (by USU, JPL, others) to improve the accuracy of ionospheric models over much of the globe.

This paper will present plans to exploit this data for input into next generation space models, including operational use of GPSRO in GAIM by summer 2011.