Observing System Simulations for the GOLD and ICON Missions

Abstract:

We present results from a comprehensive observing simulation system for remote sensing observations by the Global-scale Observations of the Limb and Disk (GOLD) and Ionospheric Connection Explorer (ICON) missions. These NASA missions to explore the terrestrial thermosphere and ionosphere are planned for launch in 2017. The GOLD instrument is a far-ultraviolet spectrograph to be deployed on a commercial communications satellite at geostationary orbit. It will measure thermospheric temperature and composition during the day, and electron density at night, to understand the global effects of solar and geomagnetic events on the thermosphere-ionosphere system. ICON is an Explorer-class satellite to be launched into low-Earth orbit at 27 degrees inclination, and will measure thermosphere and ionosphere parameters with multiple remote-sensing and in-situ instruments, to discover the connections between lower atmosphere weather and changes in the low-latitude ionosphere. Instrument development, algorithm development, and ultimately data analysis, depend on a robust capability for simulating what we expect the instruments to observe. Therefore, we are constructing a flexible software system to serve both missions. The system uses simulations from general circulation models of the atmosphere-ionosphere system as input to an airglow model, performs spectral synthesis calculations, and applies observational parameters to predict what the instruments may observe from a generalized viewing geometry that can be applied to other space-based remote sensing measurements as well. In this presentation, we describe the system architecture and methodology, and present preliminary simulation results.