WEATHER FORECASTING ACCURACY FOR FAA TRAFFIC FLOW MANAGEMENT
A WORKSHOP REPORT
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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This study was supported by Contract No. DTFA0101G10274 between the National Academy of Sciences and the Department of Transportation. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
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COMMITTEE FOR A WORKSHOP ON WEATHER FORECASTING ACCURACY FOR FAA AIR TRAFFIC CONTROL
STEVEN F.CLIFFORD (Chair),
University of Colorado, Boulder
RICHARD E.CARBONE,
National Center for Atmospheric Research, Boulder, Colorado
KELVIN DROEGEMEIER,
University of Oklahoma, Norman
JAMES E.EVANS,
Massachusetts Institute of Technology Lincoln Laboratory, Lexington
J.MICHAEL FRITSCH,
Pennsylvania State University, University Park
JOHN MCCARTHY,
Aviation Weather Associates, Inc., Costa Mesa, California
CYNTHIA MUELLER,
National Center for Atmospheric Research, Boulder, Colorado
MICHAEL J.PRATHER,
University of California, Irvine
MARILYN M.WOLFSON,
Massachusetts Institute of Technology Lincoln Laboratory, Lexington
Staff
AMANDA STAUDT, Study Director
VAUGHAN C.TUREKIAN, Study Director (until 8/31/02)
ROB GREENWAY, Project Assistant
BOARD ON ATMOSPHERIC SCIENCES AND CLIMATE
ERIC J.BARRON (Chair),
Pennsylvania State University, University Park
RAYMOND J.BAN,
The Weather Channel, Inc., Atlanta, Georgia
ROBERT C.BEARDSLEY,
Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
ROSINA M.BIERBAUM,
University of Michigan, Ann Arbor
HOWARD B.BLUESTEIN,
University of Oklahoma, Norman
RAFAEL L.BRAS,
Massachusetts Institute of Technology, Cambridge
STEVEN F.CLIFFORD,
University of Colorado/CIRES, Boulder
CASSANDRA G.FESEN,
Dartmouth College, Hanover, New Hampshire
GEORGE L.FREDERICK,
Vaisala, Inc., Boulder, Colorado
JUDITH L.LEAN,
Naval Research Laboratory, Washington, D.C.
MARGARET A.LEMONE,
National Center for Atmospheric Research, Boulder, Colorado
MARIO J.MOLINA,
Massachusetts Institute of Technology, Cambridge
MICHAEL J.PRATHER,
University of California, Irvine
WILLIAM J.RANDEL,
National Center for Atmospheric Research, Boulder, Colorado
RICHARD D.ROSEN,
Atmospheric & Environmental Research, Inc., Lexington, Massachusetts
THOMAS F.TASCIONE,
Sterling Software, Bellevue, Nebraska
JOHN C.WYNGAARD,
Pennsylvania State University, University Park
Ex Officio Members
EUGENE M.RASMUSSON,
University of Maryland, College Park
ERIC F.WOOD,
Princeton University, New Jersey
Staff
CHRIS ELFRING, Director
ELBERT W. (JOE) FRIDAY, JR., Senior Scholar
LAURIE S.GELLER, Senior Program Officer
AMANDA STAUDT, Program Officer
VAUGHAN C.TUREKIAN, Program Officer
DIANE L.GUSTAFSON, Administrative Associate
ROB GREENWAY, Project Assistant
ELIZABETH A.GALINIS, Project Assistant
ROBIN MORRIS, Financial Officer
Preface
Increasing aircraft volume in U.S. airspace presents a critical problem for air traffic flow and management. As a result, the Federal Aviation Administration (FAA) is continuously planning future air traffic control systems and protocols. Improved forecasting of severe convective weather is a critical part of this planning. Knowledge of the three-dimensional location and intensity of hazardous convective weather 2 to 6 hours ahead is central to selecting air traffic routes that will support the planned traffic with little or minimal weather delays or diversions. For traffic flow management to operate based on forecasts of convective weather, the entire aviation operations community needs to have a high-level of confidence in the forecasts and a common understanding of how they will affect operations. One of the key limitations in applying these forecasts for traffic flow management is the inherent uncertainty and complexity of making temporally and spatially well-resolved short-term forecasts (2 to 6 hours) of convection.
To help identify the limitations of convective weather forecasting and begin a dialogue on potential steps forward, the FAA asked the National Research Council (NRC) for assistance. In response, the NRC formed the Committee for a Workshop on Weather Forecasting Accuracy for FAA Air Traffic Control, which convened a 2-day exploratory workshop on June 4–5, 2002, in Washington, D.C. (see Appendix D). The workshop was a forum to address the complex issues related to research needs for convective weather forecasting. In particular, the workshop discussions explored the present and future potential in meeting required convective forecasting accuracies and how those forecasts could have greater utility to air traffic controllers, airline dispatchers, and pilots. Further, because it was indicated that the desired forecasting accuracy may not be achieved in the near future given existing
research activities, workshop participants generated a prospectus for a study to examine what is needed to reach the FAA requirements.
The first session of the workshop provided an opportunity for the operational and user communities to frame the problem. Presentations focused on identifying current activities for which improved understanding of convective weather would assist traffic flow management. The second session involved members of the research community who were assigned the task of identifying current and potential future research activities that could lead to improved 2- to 6-hour convective forecasts and more effective presentations of these forecasts. The FAA provided the following questions to help guide the presentations during the workshop’s second session:
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What approaches and strategies will be most effective to get an accurate 2- to 6-hour forecast of areas of convection for aviation use in the next 5 to 10 years? (Accurate means a desired false alarm rate (FAR) of =0.20, a desired probability of detection (POD) of =0.80, a maximal FAR of 0.30, and a minimal POD of 0.60.)
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What specific scientific enabling capabilities are needed to realize these gains and when will they be available? For example, what improvements in observations, algorithms, analyses, and numerical modeling are likely to yield the best results? What are the major gaps in the current research and development activities that need to be addressed?
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What is the most appropriate way to present the forecast in an operational setting?
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Consider the two main uses are flight planning and traffic flow management.
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Consider how the forecast will be developed and presented (i.e., purely probabilistic or deterministic).
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How will we know when we are done? What verification scheme makes the most sense from an aviation perspective?
Many workshop participants opined that the goals set by the FAA for FAR and POD were overly ambitious and, in fact, ill posed. That is, improvement in skill as measured by metrics such as FAR and POD do not necessarily translate into increased value for the end user owing to numerous mitigating influences (e.g., constraints on the overall air traffic system, nonweather impacts, and industry-government politics). In addition, such metrics, which are perfectly suited for large-scale weather features, do not
apply to spatially irregular and highly intermittent convective phenomena. An alternative set of objectives was alluded to by James Washington, of the FAA, during the first session of the workshop (see Chapter 1).
During the final session of the workshop, the committee and guests identified issues and focused research topics that need to be addressed in any follow-up activity or study.
The three chapters of this report correspond to the three sessions of the workshop. This report was prepared by the committee and recounts the discussions that took place during the workshop; the workshop format prohibited the development of findings or recommendations.
The committee thanks everyone who helped plan or who participated in the workshop, especially the invited speakers: Lance Bosart of the State University of New York at Albany; Peter Challan, James Washington, Jack Kies, and Richard Heuwinkel of the FAA; Russell Gold of the Air Transport Association; William Cranor of US Airways; Mark Phaneuf of AvMet Applications; Barbara Brown and Andrew Crook of the National Center for Atmospheric Research; Fred Foss of the Aviation Weather Center; Jack Hayes and Alexander MacDonald of the National Oceanic and Atmospheric Administration; Ross Keith of the Australian Bureau of Meteorology; and Joby Hilliker of Pennsylvania State University.
Steven F.Clifford
Chair
Acknowledgments
This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise in accordance with procedures approved by the National Research Council’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report:
Barbara G.Brown, National Center for Atmospheric Research, Boulder, Colorado
Andrew Crook, National Center for Atmospheric Research, Boulder, Colorado
R.John Hansman, Massachusetts Institute of Technology
James H.Henderson, Aviation Weather Center, Kansas City
Although the reviewers listed above provided constructive comments and suggestions, they were not asked to endorse the report’s conclusions or recommendations, nor did they see the final draft of the report before its release. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.