(Washington, DC • 1/19//07) -- The Global Assimilation of Ionospheric Measurements (GAIM) model went operational at the Air Force Weather Agency (AFWA), located at Offutt Air Force Base, on 20 December, 2006. GAIM has been under development since 1999 under the Multidisciplinary University Research Initiatives (MURI) program sponsored by the U.S. Department of Defense (DoD) and was managed by the Naval Research Laboratory's (NRL) Space Science Division.
GAIM uses a physics-based model as the basis for assimilating a diverse set of near real-time measurements. It assimilates slant total electron content (TEC) observations from up to 400 Global Positioning System (GPS) ground receiver sites, in-situ electron density observations from Defense Meteorological Satellite Program (DMSP) satellites, and bottomside electron density profiles from ionosondes. The model provides specifications and forecasts on a spatial grid that can be global, regional, or local. The specifications/forecasts are in the form of three-dimensional electron density distributions from 90 km to geosynchronous altitudes (35,000 km).
NRL scientists have begun evaluating the use of new ultraviolet (UV) space sensor data with GAIM. The sources of UV data include a suite of operational UV sensors, the Special Sensor Ultraviolet Limb Imager (SSULI), which were developed by NRL's Space Science Division. NRL scientists expect to generate exciting science from investigating the addition of UV data sets with the GAIM model. The UV-capable version of GAIM is scheduled to go operational at AFWA in December 2007.