Optimizing Earth Observing Constellations of Satellite Sensors Using ASPEN: A Proof-of-Concept Study for Global NWP and Nowcasting Applications Journal of Atmospheric and Oceanic Technology

The Advanced Systems Performance Evaluation tool for NOAA (ASPEN) is applied to the problem of optimizing the design of a constellation of sensors by calculating the scientific benefit and cost effectiveness of all possible combinations of sensors within a specified design ensemble (i.e., catalog of sensors). In this proof-of-concept study, sensors are derived from the NOAA Satellite Observing Systems Architecture (NSOSA) study, the Geostationary Extended Observations satellite system (GeoXO) program, and the COSMIC-2 mission, and the targeted applications are restricted to two examples, global NWP and a suite of 6 nowcasting applications. The results are subject to several caveats, including the use of the current version of the ASPEN inputs, and simplified methods of estimating costs. Achieving optimization adopts the approach of visualizing the results as cost-benefit “efficient frontier” scatterplots and identifying the most efficient constellations—the constellations that maximize the benefit for a given cost. The optimal constellation depends strongly on the budget, the sensor costs, the applications considered and their observational requirements and priorities, and the design ensemble of possible constellations. For illustration a simple decision rule is applied to select the optimal constellation for a given budget. In practice such guidance must be carefully considered in the context of neighboring constellations, i.e., constellations that are close to the optimal constellation in the efficient frontier scatterplot. In this study, for nominal ($2B annualized) costs the optimal constellation includes the MW LEO Sounder, GNSS RO System, and VIS IR LEO Imager for global NWP and the VIS IR GEO Imager, MW LEO Sounder, and IR GEO Sounder for nowcasting.