Publications
Automated microburst wind-shear prediction
September 1, 1994
Journal Article
Published in:
Lincoln Laboratory Journal, Vol. 7, No. 2, Fall 1994, pp. 399-426.
Summary
We have developed an algorithm that automatically and reliably predicts microburst wind shear. The algorithm, developed as part of the FAA Integrated Terminal Weather System (ITWS), can provide warnings several minutes in advance of hazardous low-altitude wind-shear conditions. Our approach to the algorithm emphasizes fundamental principles of thunderstorm evolution and downdraft development and incorporates heuristic and statistical methods as needed for refinement. In the algorithm, machine-intelligent image processing and data-fusion techniques are applied to Doppler radar data to detect those regions of growing thunderstorms and intensifying downdrafts which lead to microbursts. The algorithm then uses measurements of the ambient temperature/humidity structure in the atmosphere to aid in predicting a microburst's peak outflow strength. The algorithm has been tested in real time as part of the ITWS operational test and evaluation at Memphis, Tennessee, and Orlando, Florida, in 1994.
Summary
We have developed an algorithm that automatically and reliably predicts microburst wind shear. The algorithm, developed as part of the FAA Integrated Terminal Weather System (ITWS), can provide warnings several minutes in advance of hazardous low-altitude wind-shear conditions. Our approach to the algorithm emphasizes fundamental principles of thunderstorm evolution and...
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A microburst prediction algorithm for the FAA Integrated Terminal Weather System
April 4, 1994
Conference Paper
Published in:
SPIE, Vol. 2220, Sensing, Imaging, and Vision for Control and Guidance of Aerospace Vehicles, 4-5 April 1994, pp. 194-204.
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Summary
Lincoln Laboratory is developing a prototype of the Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) to provide improved aviation weather information in the terminal area by integrating data and products from various FAA and National Weather Service (NWS) sensors and weather information systems. The ITWS Microburst Prediction product is intended to provide and additional margin of safety for pilots in avoiding microburst wind shear hazards (Fig. 1). The product is envisioned for use by traffic managers, supervisors, controllers, and pilots (directly via datalink). Our objective is to accurately predict the onset of microburst wind shear several minutes in advance. The approach we have chosen in developing the ITWS Microburst Prediction algorithm emphasizes fundamental physical principles of thunderstorm evolution and downdraft development, incorporating heuristic and/or statistical methods as needed for refinement. Image processing and data fusion techniques are used to produce an "interest" image (Delanoy etal., 1991, 1992) that reveals developing downdrafts. We use Doppler radar data to identify regions of growing thunderstorms and probable regions of downdraft, and combine these with measures of the ambient temperature structure (height of the freezing level, lapse rate in the lower atmosphere; Wolfson 1990), total lightning flash rate, and storm motion to predict the microburst location, timing, and outflow strength. There is also a simple feedback system based on the results of the Microburst Detection algorithm that desensitizes prediction thresholds if false predictions are being reported. The following slides describe the preliminary ITWS Microburst Prediction algorithm design, and show examples of feature detector, and the algorithm output on one test case. Results from off-line testing on 17 days of data from Orlando are also presented.
Summary
Lincoln Laboratory is developing a prototype of the Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) to provide improved aviation weather information in the terminal area by integrating data and products from various FAA and National Weather Service (NWS) sensors and weather information systems. The ITWS Microburst Prediction product...
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MDCRS: aircraft observations collection and uses
August 2, 1993
Conference Paper
Published in:
5th Int. Conf. on Aviation Weather Systems, 2-6 August 1993, pp. 317-321.
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The Meteorological Data Collection and Reporting System (MDCRS) was designed for the Federal Aviation Administration (FAA) and the National Weather Service (NWS) to collect, decode, store and disseminate aircraft meteorological observations. The system, targeted primarily at improving upper air wind forecasts, was fielded in 1991.
Summary
The Meteorological Data Collection and Reporting System (MDCRS) was designed for the Federal Aviation Administration (FAA) and the National Weather Service (NWS) to collect, decode, store and disseminate aircraft meteorological observations. The system, targeted primarily at improving upper air wind forecasts, was fielded in 1991.
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Adjoint-method retrievals of microburst winds from TDWR data
May 24, 1993
Conference Paper
Published in:
26th Int. Conf. on Radar Meteorology, 24-28 May 1993, pp. 433-434.
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The simple adjoint (SA) method of Qiu and Xu (1992, henceforth referred to as QX92) was recently upgraded and tested with the Phoenix-II data for retrieving the low-altitude winds from single-Doppler scans (Xu et al. 1993a,b henceforth referred to as XQY93a,b). The major results can be briefly reviewed as follows: (i) Using multiple time-level data with the adjoint formulation makes the retrieval more accurate and less sensitive to the observational error. (ii) Imposing a weak nondivergence constraint can suppress the spurious divergence caused by the data noise and improve the retrieval. (iii) Retrieving the eddy coefficients improves the wind retrieval. (iv) Retrieving the time-man residual term improves the wind retrieval. Although the results in XQY93a,b were encouraging, the Phoenix-II data used in XQY93a,b were collected on non-storm days with chaff dispensed from an aircraft. The real challenge is to test the SA method with storm data. A microburst case is selected for the test in this paper.
Summary
The simple adjoint (SA) method of Qiu and Xu (1992, henceforth referred to as QX92) was recently upgraded and tested with the Phoenix-II data for retrieving the low-altitude winds from single-Doppler scans (Xu et al. 1993a,b henceforth referred to as XQY93a,b). The major results can be briefly reviewed as follows...
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Quantifying airport terminal area weather surveillance requirements
May 24, 1993
Conference Paper
Published in:
26th Int. Conf. on Radar Meteorology, 24-28 May 1993, pp. 47-49.
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The Federal Aviation Administration (FAA) Terminal Area Surveillance System (TASS) research, engineering, and development program was initiated in part to address future weather sensing needs in the terminal area. By the early 21st century, planned systems such as the Terminal Doppler Weather Radar (TDWR) and Airport Surveillance Radar-9 (ASR-9) will be well into their designed life cycles. Any new terminal weather surveillance system should be designed to address existing deficiencies. Key unmet weather sensing needs include detections of: true 3-dimensional winds (vs. radial component), winds in the absence of precipitation, wake vortices, total lightning, hail, icing conditions, clear air turbulence, hazardous weather cells (with adequate time and space resolution), cloud cover and cloud bases (including layers), fog, and visibility (Runway Visual Range), as well as predictions of: the atmospheric conditions mentioned above, wind shifts, microbursts, tornadoes, and snow/rainfall rates (Evans 1991a, McCarthy 1991). In this paper, we investigate the premise that hazardous weather cells are not currently being measured with adequate time and space resolution in the terminal area. Since a new surveillance system should be based on knowledge of storm dynamics, we have performed a preliminary study of update rate (using rapid scan radar to detect rapidly developing thunderstorms and precursors to the low altitude hazards such as microbursts that they produce. Other aspects of a future radar system such as multi-parameter techniques required to discriminate between ice and water phase precipitation, etc. are not considered.
Summary
The Federal Aviation Administration (FAA) Terminal Area Surveillance System (TASS) research, engineering, and development program was initiated in part to address future weather sensing needs in the terminal area. By the early 21st century, planned systems such as the Terminal Doppler Weather Radar (TDWR) and Airport Surveillance Radar-9 (ASR-9) will...
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Contributions to the American Meteorological Society's 26th International Conference on Radar Meteorology
April 1, 1993
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-199
Summary
Eleven papers contributed by the Lincoln Laboratory Weather Sensing Group to the American Meteorological Society's 26th International Conference on Radar Meteorology, to be held May 24-28, 1993 in Norman, Oklahoma, are compiled in this volume. The work reported was sponsored by several FAA programs, including Terminal Doppler Weather Radar (TDWR), Air Surveillance Radar-9 (ASR-9), Integrated Terminal Weather System (ITWS), and Terminal Area Surveillance System (TASS). The papers are based on analyses completed over the past year at Lincoln Laboratory and in collaboration with staff at the National Severe Storms Laboratory, the University of Oklahoma, Raytheon Corporation, and the FAA Technical Center in Atlantic City, NJ. The staff members of the Weather Sensing Group have documented their studies in four major areas: Operational Systems (TDWR Operational Test and Evaluation results); Radar Operations (future airport weather surveillance requirements, a "machine intelligent" gust front detection algorithm, microburst asymmetry study results, a shear-based microburst detection algorithm, and a hazard index for TDWR-detected microbursts); Signal Processing (coherent processing across multi-PRI waveforms, clutter filter design for multiple-PRT signals, and identification of anomalous propagation associated with thunderstorm outflows); and Analysis Methods (multiple-single Doppler wind analysis using NEXRAD data, and an adjoint method wind retrieval scheme).
Summary
Eleven papers contributed by the Lincoln Laboratory Weather Sensing Group to the American Meteorological Society's 26th International Conference on Radar Meteorology, to be held May 24-28, 1993 in Norman, Oklahoma, are compiled in this volume. The work reported was sponsored by several FAA programs, including Terminal Doppler Weather Radar (TDWR)...
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Summary of triple Doppler data, Orlando 1991
April 7, 1992
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-186
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Under Federal Aviation Administration (FAA) sponsorship, Lincoln Laboratory conducted an aviation weather hazard measurement and operational demonstration program during the summer of 1991 near the Orlando International Airport. Three Doppler radars were sited in a triangle around the airport, allowing triple Doppler coverage of thunderstorms and microbursts occurring there. This report contains a summary of all of the microburst producing thunderstorms that occurred within the triple Doppler region that were scanned in a coordinated fashion, during the months of June, July, August, and September, 1991. Statistics on the microburst events are presented to give an overall picture of the available data for use in analysis. The bulk of the report consists of detailed information about each triple Doppler day, including the time, location, and strength of microbursts within the triple Doppler period as well as the availability of data from supporting sensors including the ASR-9-WSR Doppler radar, radiosondes, LLWAS, Mesonet, AWOS, instrumented aircraft, ACARS, interferometer, and corona points.
Summary
Under Federal Aviation Administration (FAA) sponsorship, Lincoln Laboratory conducted an aviation weather hazard measurement and operational demonstration program during the summer of 1991 near the Orlando International Airport. Three Doppler radars were sited in a triangle around the airport, allowing triple Doppler coverage of thunderstorms and microbursts occurring there. This...
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A hybrid Cartesian windfield synthesis technique using a triple Doppler radar network
June 24, 1991
Conference Paper
Published in:
25th Int. Conf. on Radar Meteorology, 24-28 June 1991, pp. 630-633.
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The estimation of air and particle motions in storms from multiple Doppler radar measurement is a long standing problem in radar meteorology. Our research interest in understanding the relationship of electrical change generation processes above the freezing level to thunderstorm life cycle, and in the detailed quantification of the eventual low altitude divergent outflow produced by the storm, demands an accurate retrieval of air and particle motions at essentially all altitudes within the storm. We found that existing approaches had deficiencies for our needs, and have developed an improved "hybrid" approach which attempts to provide high quality estimates throughout the storm volume.
Summary
The estimation of air and particle motions in storms from multiple Doppler radar measurement is a long standing problem in radar meteorology. Our research interest in understanding the relationship of electrical change generation processes above the freezing level to thunderstorm life cycle, and in the detailed quantification of the eventual...
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Weather information requirements for terminal air traffic control automation
June 24, 1991
Conference Paper
Published in:
Fourth Int. Conf. on Aviation Weather Systems, 24-28 June 1991, pp. 208-214.
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Aviation operations in the airport terminal area, where flights converge from a number of directions onto one or two active runways, create a fundamental limitation on the capacity of the national airspace system. The U.S. Federal Aviation Administration (FAA) has recognized that the throughput of existing terminals can be increased significantly by providing the terminal air traffic control team with Terminal Air Traffic Control Automation (TATCA) tools that increase the efficiency of individual controller tasks and provide a dynamic, overall plan for traffic management throughout the terminal control region (Andrews and Welch, 1989). This latter function relies on accurate projection of traffic flow into the future (0-30 minutes) in order to automatically examine the many possible permutations of control actions. The result is a coordinated plan for the multiple (four to ten) control positions involved in the decision making processes that determine end-capacity at the runways. The FAA has launched an intensive effort to develop and implement TATCA capabilities by taking advantage of preparatory work done at NASA Ames Research Center, MITRE Corporation, and M.I.T. Lincoln Laboratory. An initial TATCA configuration, the Final Approach Spacing Tool (FAST), will be evaluated in the field beginning in 1993 and will be scheduled for possible national implementation two years later. Estimates of the economic value of TATCA-generated operational improvements, when implemented at major airports nationwide, are expected to be over $1 billion yearly by the year 2000 in reduced fuel consumption, other air carrier operating costs, and passenger time (Boswell et al., 1990). Since TATCA is first and foremost a planning system, the primary impacts of weather upon T ATCA performance involve disruption of planning. This can occur because of sudden or unexpected changes in routing, runway availability, or separation standards. In addition, errors in estimated wind produce errors in time-to-fly predictions made by the TATCA planning logic. The TATCA system must be robust with respect to weather events that commonly occur in its region of operation. This paper describes an initial study of the weather information requirements for TATCA, and their relationship to current and future systems for measurement, integration, forecasting and dissemination of meteorological data in the terminal area. A major goal is to stress the need for close coupling between ongoing initiatives in weather sensing/forecasting in the airport terminal area, and air-space capacity enhancement programs.
Summary
Aviation operations in the airport terminal area, where flights converge from a number of directions onto one or two active runways, create a fundamental limitation on the capacity of the national airspace system. The U.S. Federal Aviation Administration (FAA) has recognized that the throughput of existing terminals can be increased...
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Characteristics of thunderstorm-generated low altitude wind shear: a survey based on nationwide Terminal Doppler Weather Radar testbed measurements
December 1, 1990
Conference Paper
Published in:
Proc. 29th IEEE Conf. on Decision and Control, 5-7 December 1990, Vol. 2, pp. 682-688.
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The characteristics of microbursts and gust fronts, two forms of aviation-hazardous low altitude wind shear, are presented. Data were collected with a prototype terminal Doppler weather radar and a network of surface weather stations in Memphis, Huntsville, Denver, Kansas City, and Orlando. Regional differences and features that could be exploited in detection systems such as the associated reflectivity, surface wind shear, and temperature change are emphasized.
Summary
The characteristics of microbursts and gust fronts, two forms of aviation-hazardous low altitude wind shear, are presented. Data were collected with a prototype terminal Doppler weather radar and a network of surface weather stations in Memphis, Huntsville, Denver, Kansas City, and Orlando. Regional differences and features that could be exploited...
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