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Abstract

In this study, we introduce observing system simulation experiments (OSSE) and observing system experiments (OSE) to reconstruct the near-Earth radiation environment. This study investigates the impact of satellite measurements on different orbits and the number of spacecraft measuring the particle fluxes on the reconstruction of the radiation environment at Geostationary (GEO) orbit. We also test the sensitivity of the reconstruction of the environment to the assumed parameters of the model. The results indicate that blending the model with data, even from a single spacecraft at low Earth orbit (LEO), may significantly improve the outer belt reconstruction compared to a reconstruction without data. Additionally, the highest accuracy is achieved when multiple satellites at different orbits covering various radial distances are used. Future improvements to the model are identified. The discrepancies between the observed GEO environment and the environment reconstructed from LEO data may be stronger during storms and should be better understood. Results of the OSE may be included in synthetic data runs representing the “truth,” the so-called nature run, to provide a more realistic baseline for the OSSEs. When there is an abundance of observations at all radial distances, energies, and pitch angles, the assumptions of the code become less important as data provides enough information to constrain even an inaccurate model. This study gives an example of OSSEs and OSEs and paves the way for the routine application of the OSE and OSSE for mission planning.