NextGen Weather Requirements: An Update

Today, the National Airspace System (NAS) is the safest in the world; however, it is under significant stress. Aircraft operations are expected to grow significantly through 2025, with new super-density operations hubs and the shift to increased numbers of smaller aircraft, which require more flight operations to move equal numbers of people. There are well-founded concerns that the increased demand will exceed the ability of the current air transportation system to accommodate even moderate growth. Not all major metropolitan airports can expand operations by building more runways. In addition, the current NAS processes and procedures do not have the flexibility needed to meet the growing demand Through NextGen, new air traffic management (ATM) technologies and processes must be implemented to accommodate the higher volumes of air traffic operations safely in an efficient and environmentally sound manner.

Because of the profound impact adverse weather has on transportation, NextGen is focusing on a major new direction in aviation weather information capabilities to enable stakeholders at all levels make better operational decisions during impacting weather situations. For NextGen, weather information has a core function—identify where and when weather will impact NAS operations. Safe and efficient NextGen operations depend on enhanced aviation weather capabilities that are based on three major tenants:

• A common picture of weather for all transportation decision makers and aviation system users

• Weather information integrated directly into sophisticated decision support tool capabilities to assist decision makers

• Use of Internet-like information dissemination to realize flexible and cost-efficient access to all necessary weather information

NextGen sets forth a new way of looking at how weather information will be integrated into decision making, pro-actively supporting the air transportation system of the future. It is not about the weather products themselves; rather it is about enabling better collaborative decision making by operational stakeholders — air traffic controllers and management specialists, flight crews and dispatchers. This paper captures the evolving vision of the NextGen NAS weather concepts, needs, and functions to include the performance values that must be realized by 2025 without regard to current capabilities.

NextGen key capabilities will rely on Network-Enabled Information Access that will ensure information is available, securable, and usable in real-time for different communities of interest across the NAS. Two key components of the NextGen Weather capabilities are the 4-D Weather Data Cube (Cube) and the Single Authoritative Source (SAS). The Cube is a virtual data source that provides access through Network Enabled Operations (NEO) to all relevant aviation weather information from public and private sources as well as limited access to propriety products from domestic and non-domestic sources. The SAS is a subset of the Cube that contains gridded data fields of current and forecast aviation weather parameters. It supports the civil Air Navigation Service Provider's (ANSP), or FAA's Air Traffic Management (ATM) decisions. The SAS provides users access to common weather information for collaborative decision making (CDM) and ATM decisions, and it facilitates automated processing by ' decision support tools' (DST).

In NextGen digital, probabilistic weather information will be assimilated directly into automation platforms and DSTs, significantly improving decision making and risk management. DSTs may be used to plan efficient routes and predict deviations consistent with safe and efficient flight trajectories near emerging weather hazards. They may also indicate the “hardness” or “softness” of weather constraints and the associated risks to a specific flight, in a specific airframe, over a specific location or along an intended flight trajectory. For example, a User DST such as the User Request Evaluation Tool (URET) blends SAS weather information with operations information to provide re-routes that avoid turbulence and convection; or the Traffic Management Advisor (TMA) integrates SAS wind and convection information to align the flow of arrivals and departures.

To document the NextGen weather requirements, the Joint Planning and Development Office (JPDO) established a Weather Functional Requirements Study Team and published the Four Dimensional Weather Functional Requirements for Next Generation Air Transportation System (NextGen) Air Traffic Management, Version 0.1 of January 18, 2008. The FAA subsequently convened a multi-disciplinary NextGen Weather Performance Requirement Team (NWPRT) to develop the associated weather performance requirements.

The NWPRT used the JPDO developed functional weather requirements as the initial baseline to develop the NextGen weather performance requirements. During the performance review process, some new functions were added while others were deleted and the functional requirements were re-baselined. NAS level performance requirements were then developed for all the functional requirements. The resulting 10,000+ weather requirements are intended to meet all weather service needs for both terrestrial and space operations circa 2025.

Two primary sub teams of the NWPRT developed the performance requirements associated with 'Observation Atmospheric and Space Conditions' and ‘Forecast Atmospheric and Space Conditions' respectively. The Forecast Sub team spun off a new Probability sub team to tackle the challenge of risk management in a statistical framework underlying predictive products that decision support tools (DSTs) and people (users) could understand and to develop the probabilistic forecast functional requirements. The FAA anticipates that the probabilistic forecast performance requirements will be completed with six months. These FAA weather functional and performance requirements are not allocated. However, the FAA's NWPRT made an initial draft allocation of those requirements to the SAS, the Cube, users' DST, and the Weather Enterprise Decision Support Service Tool.

These NAS-level functional and performance requirements have been distributed for user and meteorological community review. Once that review has been completed and comments resolved, these weather requirements will be delivered to the Joint Planning and Development Office for additional review as draft JPDO weather requirements. The FAA will use modeling and simulations with service providers (e.g., traffic flow management specialists) and users to finalize these weather requirements. At that time, the complete set of agency weather performance requirements will be allocated to specific weather systems within the NAS Enterprise Architecture and to research and development as necessary.