In this study we apply the Advanced Systems Performance Evaluation tool for NOAA (ASPEN), to support design activities for GeoXO, NOAA's program for the next-generation operational geostationary meteorological and space weather satellites. ASPEN is a dynamic and user friendly tool that rapidly assesses the value of environmental data obtained from observing systems. ASPEN was designed to help optimize and evaluate observing systems architecture solutions to meet as many needs as possible across a wide range of environmental applications. ASPEN provides a uniform interface in terms of geophysical observables and their attributes to compare the capabilities of different individual sensors, or constellations of sensors and to capture the requirements and priorities of applications. ASPEN fundamentally tries to answer the following questions: What knowledge of the environment is required by the multitude of applications? How well can observing systems measure the environment in general? To what extent do these observing system capabilities match the applications requirements? How can we account for varying levels of prioritization among observables and their attributes, when considering applications and their varying level of importance to the mission? A preliminary version of ASPEN is described here and applied to rank multiple potential configurations of GeoXO. In the application to GeoXO, ASPEN was an additional novel tool for assessing the relative benefit of an ensemble of proposed GeoXO sensor constellations.

We provide consistent theoretical and empirical assessments of the major driving factors of the information content and retrieval performance for current and potential future microwave (MW) sounders. For the specific instrument concepts assessed, we find that instrument noise is a major driver, impacting vertical resolution as measured by the degrees of freedom for signal as much as 50%. We also observe diminished performance in the 118 GHz temperature sounding band as compared to the 50–60 GHz band, which is largely due to the increased sensor noise in the assessed 118 GHz sensor for comparable channels—a reduction in the performance gap between 118 GHz and 50 GHz bands can be obtained with a reduction of instrument noise in the 118 GHz temperature sounding channels. As expected, scene-type also significantly impacts the vertical resolution, emphasizing the importance of separating clear, cloudy, rainy, and icy conditions when evaluating instrument performance.