Reanalysis of plasma measurements at geosynchronous orbit

Retrospective analyses of spacecraft anomalies, especially surface charging, require information about the local plasma environment. Such information is usually not available at geosynchronous orbit because most vehicles lack appropriate sensors. We have constructed a nearly continuous hourly database covering four plasma moments at geosynchronous orbit: density and temperature for hot (energies > 100 eV) protons and electrons. The four moments are provided for 24 hourly fiducial local time bins and cover the years 1990-2005. We apply an ensemble of simple models to fill in'' the local time gaps between plasma measurements at geosynchronous orbit made by Los Alamos sensors. Validation on artificial data gaps shows that the reconstruction has rank order correlations ranging from 0.65 to 0.97, depending on bulk moment and local time. As a demonstration, we include a comparison of our reanalysis electron temperature to on-orbit surface charging measurements at a vehicle that lacks a plasma sensor. In addition to anomaly analyses, the reanalysis database we have produced can be used to provide geosynchronous boundary conditions for numerical simulations of the inner magnetosphere and temporal variations at a single location for statistical studies.