An Earth System Approach for NOAA's Next-Generation Observation System Architecture

There is a continuing and growing need to take a comprehensive view of how we assess the value and impact of observing systems. This is important in many areas, including prioritizing investments in the observing systems portfolio, ensuring cost-effectiveness, optimizing system performance, planning the next-generation space flight and ground architectures, and negotiating international agreements to optimize international satellite data contributions. NOAA, for example, faces questions regarding the contributions to the WMO Global Observing System (GOS)—questions such as “What observations provide the best return on investment?” and “What combination of observing systems is optimal?” These questions are important for all of NOAA’s observing system portfolio, especially for satellite-borne sensors due to the associated large capital costs and long-term operations.

The authors will describe the Earth system domains, variables, and attributes necessary for capturing observational needs in a solution-agnostic manner. One goal is to provide a framework to facilitate fair comparisons of the information content of individual geophysical variables either provided by observing systems or required by applications/users. This will allow us to prioritize existing and proposed observing systems regarding their information content and benefit to data collection needs and associated costs. In this context, defining the performances of sensors, observing systems, and/or constellations of sensors in terms of the variable and attributes defined here can be viewed as a translation of sensor characteristics (e.g., for spaceborne radiometers: spectral range, sampling, channel bandwidth, and noise as well as spatial coverage and revisit time) into geophysical variable retrieval performance figures that are readily compared to requirements of applications and users.

Providing a holistic definition of the Earth system environment would have benefits to many downstream users, including support for NOAA’s move toward an Earth system approach for observations and forecasting. In addition, a full description of the Earth system will provide guidance to optimize the next-generation space-based observation system architecture to meet the needs of multiple applications requiring different observations of the Earth system.

We will use the resulting description of the Earth system in the Advanced Systems Performance Evaluation Tool for NOAA (ASPEN) —a dynamic and user-friendly tool that rapidly assesses the value of environmental data obtained from observing systems. ASPEN provides numerical scores of the benefits of existing and proposed sensors and constellations applied to a single or group of applications. It is designed to be a science-based approach to performing the comparative assessment of observation systems to support the decision process that leads to the design, selection, and, ultimately, the deployment of new space assets and associated ground systems.