Publications
Forecast confidence measures for deterministic storm-scale aviation forecasts
February 5, 2014
Conference Paper
Published in:
4th Aviation, Range, and Aerospace Meteorology Special Symp., 2-6 February 2014.
Summary
Deterministic storm-scale weather forecasts, such as those generated from the FAA's 0-8 hour CoSPA system, are highly valuable to aviation traffic managers. They provide forecasted characteristics of storm structure, strength, orientation, and coverage that are very helpful for strategic planning purposes in the National Airspace System (NAS). However, these deterministic weather forecasts contain inherent uncertainty that varies with the general weather scenario at the forecast issue time, the predicted storm type, and the forecast time horizon. This uncertainty can cause large changes in the forecast from update to update, thereby eroding user confidence and ultimately reducing the forecast's effectiveness in the decision-making process. Deterministic forecasts generally lack objective measures of this uncertainty, making it very difficult for users of the forecast to know how much confidence to have in the forecast during their decision-making process. This presentation will describe a methodology to provide measures of confidence for deterministic storm-scale forecasts. The method inputs several characteristics of the current and historical weather forecasts, such as spatial scale, intensity, weather type, orientation, permeability, and run-to-run variability of the forecasts, into a statistical model to provide a measure of confidence in a forecasted quantity. In this work, the forecasted quantity is aircraft blockage associated with key high-impact Flow Constrained Areas (FCAs) in the NAS. The results from the method, which will also be presented, provide the user with a measure of forecast confidence in several blockage categories (none, low, medium, and high) associated with the FCAs. This measure of forecast confidence is geared toward helping en-route strategic planners in the NAS make better use of deterministic storm-scale weather forecasts for air traffic management.
Summary
Deterministic storm-scale weather forecasts, such as those generated from the FAA's 0-8 hour CoSPA system, are highly valuable to aviation traffic managers. They provide forecasted characteristics of storm structure, strength, orientation, and coverage that are very helpful for strategic planning purposes in the National Airspace System (NAS). However, these deterministic...
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Velocity estimation improvements for the ASR-9 Weather Systems Processor
February 2, 2014
Conference Paper
Published in:
American Meteorological Society Annual Meeting, 2-6 February 2014.
Summary
The Airport Surveillance Radar (ASR-9) is a rapid-scanning terminal aircraft detection system deployed at airports around the United States. To provide cost-effective wind shear detection capability at medium-density airports, the Weather Systems Processor (WSP) was developed and added on to the ASR-9 at 35 sites. The WSP on the ASR-9 is capable of utilizing dual fan-beam estimates of reflectivity and velocity in order to detect low-level features such as gust fronts, wind shear, and microbursts, which would normally be best detectable by a low-scanning pencil beam radar. An upgrade to the ASR-9 WSP, which is currently ongoing, allows for additional computational complexity in the front-end digital signal processing algorithms compared to previous iterations of the system. This paper will explore ideas for improving velocity estimates, including low-level dual beam weight estimation, de-aliasing, and noise reduction. A discussion of the unique challenges afforded by the ASR-9's block-stagger pulse repetition time is presented, along with thoughts on how to overcome limitations which arise from rapid-scanning and the inherent lack of pulses available for coherent averaging.
Summary
The Airport Surveillance Radar (ASR-9) is a rapid-scanning terminal aircraft detection system deployed at airports around the United States. To provide cost-effective wind shear detection capability at medium-density airports, the Weather Systems Processor (WSP) was developed and added on to the ASR-9 at 35 sites. The WSP on the ASR-9...
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Initial assessment of wind forecasts for Airport Acceptance Rate (AAR) and Ground Delay Program (GDP) planning
January 29, 2014
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-414
Summary
The planning and execution of the Airport Acceptance Rate (AAR) for major metroplex airports is a complex and critical function of traffic managers in the National Airspace System (NAS). Despite the importance of AAR planning, traffic managers currently have no widely available decision support to provide guidance for runway selection and the determination of a sustainable AAR. The AAR Decision Support Capability (AARDSC), currently under development as part of the Collaborative Air Traffic Management Technology Work Package 4 (CATMT WP4), will provide such guidance. This report provides an initial analysis of the impacts of surface winds and winds aloft on the key factors associated with the AAR (the selection of runway configuration and aircraft ground speed and spacing on final approach) and the capabilities of currently available weather forecasts to accurately predict those impacts. The report was limited in scope by the schedule and available resources, and is intended as a foundation for a comprehensive forecast assessment in follow-on work. Surface wind forecasts from the Terminal Aerodome Forecast (TAF) and numerical prediction models (the High Resolution Rapid Refresh [HRRR], Rapid Refresh [RAP] and Rapid Update Cycle [RUC], collectively described as "MODEL") were compared to observed winds gathered from METAR reports as Newark International Airport (EWR). TAF and METAR were compared for 639 days of operations from 2011-2013. MODEL forecasts and METAR were compared for 21 days of operation, 16 of which had Traffic Management Initiatives (TMI) in place to mitigate adverse weather impacts. Winds aloft were translated into several wind impact metrics. The impacts of winds aloft forecast errors were evaluated by comparing impact metrics calculated from MODEL forecasts with those calculated from analysis fields for the 21 case days. Forecasts were evaluated at horizons of 2, 4, 6, and 8 hours.
Summary
The planning and execution of the Airport Acceptance Rate (AAR) for major metroplex airports is a complex and critical function of traffic managers in the National Airspace System (NAS). Despite the importance of AAR planning, traffic managers currently have no widely available decision support to provide guidance for runway selection...
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Review of Systems-Theoretic Process Analysis (STPA) method and results to support NextGen concept assessment and validation
October 25, 2013
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-427
Summary
This report provides an assessment of the applicability of Systems-Theoretic Process Analysis (STPA) to perform preliminary risk-based modeling of complex NextGen concepts, based on the observed application of STPA to Interval Management-Spacing (IM-S) as a case study. The report also considers the potential use of STPA as a formal tool for safety analysis at the Federal Aviation Administration. This report's sources include a report documenting the application of STPA performed by the MIT Systems Engineering Research Lab (SERL), previous reports, and input from other staff and aviation subject-matter experts.
Summary
This report provides an assessment of the applicability of Systems-Theoretic Process Analysis (STPA) to perform preliminary risk-based modeling of complex NextGen concepts, based on the observed application of STPA to Interval Management-Spacing (IM-S) as a case study. The report also considers the potential use of STPA as a formal tool...
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An applications architecture to support FAA wake turbulence mitigation systems development and deployment
October 9, 2013
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-412
Summary
The Wake Turbulence Program within the Federal Aviation Administration (FAA) is considering a number of new procedures for safely reducing the wake vortex spacing requirements between aircraft. One category of procedures investigates wind-dependent procedures, i.e., procedures that can be applied when wind conditions are expected to transport the wake from a lead aircraft away from the path of a trailing aircraft. MIT Lincoln Laboratory developed a Wind Forecast Algorithm (WFA) to determine when conditions allow these wind-dependent procedures to be available to traffic managers. The baseline WFA is used within the Wake Turbulence Mitigation for Departures (WTMD) system, which establishes spacing procedures for departures on closely spaced parallel runways. A number of new procedures are also under consideration, each of which will require a modification and/or expansion of the baseline WFA. With time, the volume and number of disparate data sources used in the development process has steadily increased to the point where the existing development environment has become cumbersome and inadequate. As a result, through support of the FAA Wake Turbulence Program, MIT Lincoln Laboratory has undergone a complete overhaul of the computer processing and storage architecture used for WFA development. This will serve two main purposes. First, it will greatly expedite the development process, which is highly iterative and requires increasingly large volumes of data. Second, an updated architecture design will allow for an expeditious transition of developmental systems into the operational environment within FAA's NextGen framework. A key focus of this report describes how the new design is sufficiently compatible and flexible to serve within this anticipated FAA framework. The unified application architecture and infrastructure being designed and implemented will support continuing development, playback requirements, and real-time deployments. This architecture is composed of several application components including a wind data extract-transform-loaf (ETL) application, the WFA algorithm, and a display interface to accomodate both the development process and for potential use within the FAA operational environment. The Wind-ETL application component acquires, processes, and archives wind data from a variety of NOAA-based hourly forecasts and airport-vicinity weather measurement equipment. This wind data is ingested by the WFA, which computes and disseminates its availability predictions to the WTMx Display application component, which archives these predictions and also allows for presentation to the airport tower supervisor via the WTMx display user interface decision support tool. This architecture is designed to be flexible to accepting new weather data feeds, scalable to the high bandwidth and processing and storage capabilities required, provide sufficient automation and self-healing capabilities, and portable to allow its introduction into alternate facility sites and its integration into other FAA software systems.
Summary
The Wake Turbulence Program within the Federal Aviation Administration (FAA) is considering a number of new procedures for safely reducing the wake vortex spacing requirements between aircraft. One category of procedures investigates wind-dependent procedures, i.e., procedures that can be applied when wind conditions are expected to transport the wake from...
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Wind-shear detection performance analysis for MPAR risk reduction
September 16, 2013
Conference Paper
Published in:
36th Conf. on Radar Meteorology, 16 September 2013.
Summary
Multifunction phased array radars (MPARs) of the future that may replace the current terminal wind-shear detection systems will need to meet the Federal Aviation Administration's (FAA) detection requirements. Detection performance issues related to on-airport siting of MPAR, its broader antenna beamwidth relative to the Terminal Doppler Weather Radar (TDWR), and the change in operational frequency from C band to S band are analyzed. Results from the 2012 MPAR Wind-Shear Experiment are presented, with microburst and gust-front detection statistics for the Oklahoma City TDWR and the National Weather Radar Testbed (NWRT) phased array radar, which are located 6 km apart. The NWRT has sensitivity and beamwidth similar to a conceptual terminal MPAR (TMPAR), which is a scaled-down version of a full-size MPAR. The micro-burst results show both the TDWR probability of detec-tion (POD) and the estimated NWRT POD exceeding the 90% requirement. For gust fronts, however, the overall estimated NWRT POD was more than 10% lower than the TDWR POD. NWRT data are also used to demonstrate that rapid-scan phased array radar has the potential to enhance microburst prediction capability.
Summary
Multifunction phased array radars (MPARs) of the future that may replace the current terminal wind-shear detection systems will need to meet the Federal Aviation Administration's (FAA) detection requirements. Detection performance issues related to on-airport siting of MPAR, its broader antenna beamwidth relative to the Terminal Doppler Weather Radar (TDWR), and...
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Validation of NEXRAD radar differential reflectivity in snowstorms with airborne microphysical measurements: evidence for hexagonal flat plate crystals
September 16, 2013
Conference Paper
Published in:
36th Conf. on Radar Meteorology, 16 September 2013.
Summary
This study is concerned with the use of cloud microphysical aircraft measurements (the Convair 580) to verify the origin of differential reflectivity (ZDR) measured with a ground-based radar (the WSR-88D KBUF radar in Buffalo, New York). The underlying goal is to make use of the radar measurements to infer the presence or absence of supercooled water, which may pose an icing hazard to aircraft. The context of these measurements is the investment by the Federal Aviation Administration in the use of NEXRAD polarimetric radar and is addressed in the companion paper by Smalley et al. (2013, this Conference). The highlight of the measurements on February 28, 2013 was the finding of sustained populations of hexagonal flat plate crystals over a large area northwest of the KBUF radar, in conditions of dilute and intermittent supercooled water concentration. Some background discussion is in order prior to the discussion of the aircraft/radar observations that form the main body of this study. The anisotropy of hydrometeors, the role of humidity and temperature in crystal shape, and the common presence of hexagonal flat plate crystals in the laboratory cold box experiment are all discussed in turn.
Summary
This study is concerned with the use of cloud microphysical aircraft measurements (the Convair 580) to verify the origin of differential reflectivity (ZDR) measured with a ground-based radar (the WSR-88D KBUF radar in Buffalo, New York). The underlying goal is to make use of the radar measurements to infer the...
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Multifunction Phased Array Radar (MPAR): achieving Next Generation Surveillance and Weather Radar Capability
September 1, 2013
Journal Article
Published in:
J. Air Traffic Control, Vol. 55, No. 3, Fall 2013, pp. 40-7.
Topic:
R&D area:
Summary
Within DOT, the FAA has initiated an effort known as the NextGen Surveillance and Weather Radar Capability (NSWRC) to analyze the need for the next generation radar replacement and assess viable implementation alternatives. One concept under analysis is multifunction radar using phased-array technology -- Multifunction Phased Array Radar or MPAR.
Summary
Within DOT, the FAA has initiated an effort known as the NextGen Surveillance and Weather Radar Capability (NSWRC) to analyze the need for the next generation radar replacement and assess viable implementation alternatives. One concept under analysis is multifunction radar using phased-array technology -- Multifunction Phased Array Radar or MPAR.
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Wind-shear detection performance study for multifunction phased array radar (MPAR) risk reduction
June 12, 2013
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-409
Summary
Multifunction phased array radars (MPARs) of the future that may replace the current terminal wind-shear detection systems will need to meet the Federal Aviation Administration's (FAA) detection requirements. Detection performance issues related to on-airport siting of MPAR, its broader antenna beamwidth relative to the TDWR, and the change in operational frequency from C band to S band are analyzed. Results from the 2012 MPAR Wind-Shear Experiment (WSE) are presented, with microburst and gust-front detection statistics for the Oklahoma City TDWR and the National Weather Radar Testbed (NWRT) phased array radar, which are located 6 km apart. The NWRT has sensitivity and beamwidth similar to a conceptual terminal MPAR (TMPAR), which is a scaled-down version of a full-size MPAR. The microburst results show both the TDWR probability of detection (POD) and the estimated NWRT POD exceeding the 90% requirement. For gust fronts, however, the overall estimated NWRT POD was more than 10% lower than the TDWR POD. NWRT data is also used to demonstrate that rapid-scan phased array radar has the potential to enhance microburst prediction capability.
Summary
Multifunction phased array radars (MPARs) of the future that may replace the current terminal wind-shear detection systems will need to meet the Federal Aviation Administration's (FAA) detection requirements. Detection performance issues related to on-airport siting of MPAR, its broader antenna beamwidth relative to the TDWR, and the change in operational...
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Sector workload model for benefits analysis and convective weather capacity prediction
June 10, 2013
Conference Paper
Published in:
10th USA/Europe Air Traffic Management Research and Development Sem., ATM 2013, 10-13 June 2013.
Topic:
R&D area:
R&D group:
Summary
En route sector capacity is determined mainly by controller workload. The operational capacity model used by the Federal Aviation Administration (FAA) provides traffic alert thresholds based entirely on hand-off workload. Its estimates are accurate for most sectors. However, it tends to over-estimate capacity in both small and large sectors because it does not account for conflicts and recurring tasks. Because of those omissions it cannot be used for accurate benefits analysis of workload-reduction initiatives, nor can it be extended to estimate capacity when hazardous weather increases the intensity of all workload types. We have previously reported on an improved model that accounts for all workload types and can be extended to handle hazardous weather. In this paper we present the results of a recent regression of that model using an extensive database of peak traffic counts for all United States en route sectors. The resulting fit quality confirms the workload basis of en route capacity. Because the model has excess degrees of freedom, the regression process returns multiple parameter combinations with nearly identical sector capacities. We analyze the impact of this ambiguity when using the model to quantify the benefits of workload reduction proposals. We also describe recent modifications to the weather-impacted version of the model to provide a more stable normalized capacity measure. We conclude with an illustration of its potential application to operational sector capacity forecasts in hazardous weather.
Summary
En route sector capacity is determined mainly by controller workload. The operational capacity model used by the Federal Aviation Administration (FAA) provides traffic alert thresholds based entirely on hand-off workload. Its estimates are accurate for most sectors. However, it tends to over-estimate capacity in both small and large sectors because...
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