• A common picture of the weather for all transportation decision makers and aviations system users
• Weather integrated directly into sophisticated decision support capabilities to assist decision makers
• Utilization of Internet-like information dissemination to realize flexible and cost-efficient access to all necessary weather information.
Air Traffic Management (ATM) personnel, aviation industry representatives, pilots, and weather experts studying the NextGen paradigm have determined that a network-enabled, four-dimensional weather data cube (4-D Wx Data Cube) is the best choice to ensure that accurate weather information is integrated into NextGen operational decision-making. A subset of this 4-D Wx Data Cube, known as the 4-D Wx Single Authoritative Source (4-D Wx SAS), provides seamless, consistent, de-conflicted weather information for ATM decisions. The 4-D Wx SAS facilitates the integration of weather information directly into operational decision support tools.
In June 2007, the Joint Planning and Development Office (JPDO) Senior Policy Committee approved a request for agency resources to form a JPDO Weather Working Group-sponsored study team to perform a weather functional requirements analysis. The Weather Functional Requirements Study Team was asked to:
• Identify and document in greater detail NextGen aviation transportation system weather information functional capability requirements (delivered through a 4-D cube concept) as envisioned in the NextGen Concept of Operations (ConOps), including data attributes (e.g., resolution [spatial and temporal], data latency, refresh, reliability, integrity, and information content)
• Develop and document cost, schedule, and performance attributes at the task level for the 4-D weather cube.
The JPDO requested that subject matter experts (SME) representing government stakeholders from the Federal Aviation Administration (FAA), the National Oceanic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA), and the Department of Defense (DOD) be made available to comprise the study team. The SME expertise included meteorologists, system engineers, and one cost/budget analyst.
One key study team accomplishment was the 4-D Wx SAS definition, which was developed in conjunction with the JPDO Weather Policy Study Team. The 4-D Wx SAS represents the machine-readable, network-enabled, geo- and time-referenced weather information available via network-enabled communications and has the following characteristics:
• Includes current observations, interpolated current conditions, and predictions of future conditions
• Supports probabilistic decision aids
• Provides a seamless, consistent, de-conflicted common weather picture for integration into operational decisions that is available to all ATM decision makers.
The study team's primary task was to provide the necessary functional and limited performance NextGen weather requirements for the 4-D Wx SAS to support NextGen operations. For JPDO agencies to plan and implement NextGen, a functional analysis to the lowest level is essential, as is the development of the associated functional and performance requirements. Functional analysis determines those activities that must be performed in order to identify a stakeholder's need. It leads to a complete set of requirements that satisfies that need and improves integration, discourages predefined solutions, and enables the incorporation of new and innovative designs and solutions. For this task, the study team extracted operational needs from the NextGen ConOps v2.0 and then decomposed them until sufficient detail existed to determine the high-level weather functions. These high-level functions were iteratively decomposed to determine all required NextGen weather functions. The team translated the resultant functions into limited functional and performance requirements.
The team was also tasked to develop and document cost, schedule, and performance attributes at the task level for the 4-D Wx SAS. SMEs, using two comparables for the development and implementation of the 4-D Wx SAS, estimated the rough order of magnitude (ROM) costs. The National Weather Service's (NWS) National Centers for Environmental Prediction (NCEP) prepared the estimate for the development of the capability to create the weather information in the 4-D Wx SAS and the operational cost associated with this capability. NWS developed this cost estimate using today's modeling development and system operations to estimate the cost of meeting the 4-D Wx SAS functional and performance requirements detailed in the 4-D Functional Requirements For NextGen ATM report, January 18, 2008.
Using the JPDO developed functional requirements, the FAA developed its NextGen weather performance requirements for the 4-D Wx Cube (outside the 4-D Wx SAS). The participants in the requirements development team included representatives from the terminal, en route, system operations, NextGen and operations planning, three GA pilots (two with multiple engine experience), one controller with both terminal and en route experience, two people with flight service station experience and two National Weather Service representatives. The team determined the spatial and temporal resolution required in these performance requirements based on NextGen concepts (e.g., super density operations and trajectory based operations) and air traffic domain. These end-state performance requirements include both observed and forecast weather parameters and will be validated by all NextGen decision makers early in 2009. Afterwards, the FAA will use modeling and simulation with decision maker participation to produce a final NextGen set of weather requirements.