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NWS Next Generation Air Transportation System (NextGen)

4-D Weather Single Authoritative Source

  1. Although this definition of the SAS is applicable at NextGen Full Operating Capability (FOC), the required attributes of the SAS (see Note 3) will improve from IOC to FOC.  The SAS will evolve based on the maturity of operational decisions (e.g., Trajectory-Based Operations) and the ability of meteorological science to meet the weather information requirements of those decisions.
  2. The 4-D Wx Data Cube will be comprised of aviation-relevant observations, analyses, forecasts (including probability), and climatology organized by 3-dimensional spatial (latitude, longitude, altitude) and time components, including space weather information.
  3. In this context, “optimal representation” indicates that the weather information has been de‑conflicted (i.e., a single answer for any weather parameter at any x, y, z and t) and has the required consistency, accuracy, reliability, availability, and accessibility.  These determinations are made by the “SAS Domain Authority.”
  4. The JPDO Concept of Operations for the Next Generation Air Transportation System (version 2.0, 13 June 2007) defines Air Navigation Service Provider as follows:  “An organization responsible for and authorized to provide air traffic management (ATM) services; communications, navigation, and surveillance (CNS) services; meteorological services for air navigation; and aeronautical information services.”
  5. ICAO Document 9854 Global Air Traffic Management Operational Concept and the JPDO Concept of Operations for the Next Generation Air Transportation System (version 2.0, 13 June 2007) define ATM as follows:  “The dynamic, integrated management of air traffic and airspace — safely, economically and efficiently — through the provision of seamless services and in collaboration with all parties.”  In addition, Appendix A of ICAO Document 9854 describes the ATM community as including the following:  aerodrome community, airspace providers, airspace users, ATM service providers, ATM support industry, ICAO, regulatory authorities, and states.
  6. Neither the ANSP nor operators are prohibited from using weather information provided by commercial vendors in their respective decision-making processes.  However, if the SAS domain authority defines as part of the SAS weather information acquired from a commercial vendor, that information must be made available to all other users of the NAS.


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