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50 NextGen will require a systemwide transformation, which data sets with a grid size of about 8 km. This is significantly is expected to be completed in 2025, with initial system coarser than the density mappings that can be provided by enhancements beginning to come on line by 2012. Weather surface-based total lightning detection systems, but will be information and weather observations are crucial to NextGen, provided at no cost to the user and with relatively uniform and the required upgrades will impact all elements of our resolution coverage over CONUS lightning activity areas. Prior aviation weather system (35). to launch, there will be a number of efforts to use currently To achieve NextGen goals, all aspects of the aviation system, available regional ground-based total lightning networks to including airport and ramp operations, will be tightly inte- test the potential application of this new satellite-based data grated to provide a shared awareness of all aspects of the source at airports. system for joint planning and system management (36). Weather information will be fully integrated in the NextGen Summary and Recommendations environment, with observational data and forecast products available from a single authoritative source and distributed From the safety perspective, currently available lightning through a network-enabled weather information sharing detection and warning systems seem to be meeting airport system. At the core of this capability will be a virtual four- and aviation industry needs. There are, however, a number of dimensional database formed by expert system fusion of var- potential options for enhancing and improving the current ious gridded fields, model output, statistical systems, climate systems to reduce the number and duration of ramp closures information, observations, and human forecaster input (37). and to improve operational efficiency, including the following: These anticipated changes may well become a vehicle for more standardization of weather products, including lightning Refining the warning algorithms and criteria through the detection and warning systems. JPDO planning, however, is use of self-monitoring software. While this approach is not still in its early stages, and the specific details of the new pro- necessarily guaranteed to shorten ramp closures, it would cedures and policies, and how they will be implemented, will provide an objective standard for selecting warning crite- take time to be resolved. The concept of a "single authoritative ria to balance safety and efficiency. source" for weather information suggests increased central- Additional meteorological data sets, primarily meteoro- ization of weather observations and dissemination of weather logical radar data, can be used to better define the spatial information. The "four-dimensional weather information and temporal limits of the lightning hazard. Using inte- database," will, however, be a virtual database and not neces- grated data sets to define the geometrical extent of the sarily mean a single information provider. The database lightning cells and then tracking their evolution and move- concept also includes provisions for restricted or classified ment should be particularly valuable. information for DoD users, as well as ways to include propri- Most specifically, lightning cell tracking and echo move- etary commercial products. This will take time to sort out, ment vectors may also be used to adjust the warning criteria but NextGen clearly has a potential to change the way ramp to minimize the number of short-duration ramp closures operations are managed and the way lightning detection and triggered by storms that are not likely to impact the airport warning services are provided to all users of the air trans- area. portation system. Recent demonstrations and tests of total lightning systems are showing great promise for enhancing and refining lightning warnings. Limited regional total lightning net- GOES-R Geostationary Lightning Mapper works are currently available for experimentation, but rou- Sometime after 2014, the United States will launch the tine availability of these systems for operational use is still first of its new generation of geostationary meteorological years away. satellites--the GOES-R series of spacecraft. These new satel- Given the economic pressure on the aviation industry to lite systems will, for the first time, include a GLM. The GLM reduce costs, enhancements in lightning detection and is an optical total lightning detector that can detect and locate warning systems will need to be critically reviewed to de- lightning strokes over most of the visible earth disk with very termine their cost effectiveness. Software enhancements high efficiency (38). and optimization of warning criteria should be a relatively The GLM will provide real-time lightning information to low cost system enhancement, but would have to be im- ground users. While the details of the dissemination system plemented by lightning warning system vendors. The costs are still being developed, it is likely that the GLM will provide of integrating radar and other meteorological observations information on the location and extent of lightning discharges, may be able to be minimized by making use of existing data including two-dimensional flash density products. From geo- integration platforms, such as ITWS and WSDDM, or by stationary orbit, the instrument is expected to provide gridded moving the processing to regional or national analysis

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51 centers (either governmental or commercial), and then sensing may be able to remove any need for lightning-specific transmitting only the information needed for the local detection hardware to be installed or maintained at individ- airport display systems and warning decisions to each ual airports. If successful, this transformation should result individual airport system. Another way to realize signifi- in lower costs to airports and airlines, while preserving or cant cost savings would be to develop new technologies improving lightning hazard identification. Airport-specific and new algorithms to detect and monitor thunderstorms studies should also be directed at evaluating the performance that develop over the airport, and then minimize or elim- of currently available lightning systems, optimizing the warn- inate the use of EFMs as an essential component in airport ing criteria for these systems, and quantifying the potential lighting warning systems. tradeoff between safety and efficiency. Another topic for additional research and evaluation can NextGen and, to a lesser extent, lightning observations address ramp lightning facility mitigation strategies. For from the next generation of geostationary weather satellites example, it may be possible to design a facilities mitigation may eventually provide enhanced capabilities or increased concept, where ramp workers could safely unload baggage federal support, but they cannot be counted on in the near during a lightning event. A program could be developed future. Those developments are too far off to influence near- where a set of ramp mitigation ideas would be collected via term operational decisions, but should be monitored for survey and analyzed. A cost/benefit analysis could then be de- future potential. For current planning purposes, airports and veloped so each airport could calculate the potential utility of airlines will need to depend on commercial vendors and cur- introducing various ramp mitigation strategies based on their rent technology. individual circumstances. We recommend that industry trade groups such as the To the extent possible, we urge airports and airlines that American Association of Airport Executives, Airports Council operate lightning detection and warning systems to collabo- InternationalNorth America, and Air Transport Association rate with research efforts designed to test or enhance warning encourage, on a voluntary basis, the routine collection and products by granting researchers access to monitor the per- reporting of ramp closure statistics and associated lightning- formance of their installed operational systems and observe related injuries and material damage. ramp operations. There are a number of important follow-on studies that will Lightning is but one of many weather factors causing be needed to further the advancement of improved lightning economic loss for the airlines. It would seem appropriate to warning systems for airports. Of particular importance is the conduct a follow-on study to analyze all weather factors consideration and evaluation of remote sensing observations, affecting airline delays, such as, high winds, heavy rains, snow, most likely meteorological radars and total lightning systems, ice, and fog. This analysis would employ a different economic as replacements for EFMs in operational lightning detection approach than used for lightning-caused delays and enable and warning systems. Warning systems based exclusively on a focus on air traffic flow delays, with ramp closings as a routine surface observations, numerical models, and remote secondary impact.