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The capabilities and limitations of using the ASR-9 as a terminal area precipitation sensor

September 7, 1997
  |
Conference Paper
Author:
Bradley A. Crowe
…
Published in:
28th Conf. on Radar Meteorology, 7-12 September 1997.
Topic:
aviation weather
R&D area:
R&D group:

Summary

The Airport Surveillance Radar (ASR-9) weather channel is an invaluable tool to air-traffic and flight management specialists. The precipitation data from this sensor is currently displayed on air-traffic specialists' radar scopes and is incorporated into the Integrated Terminal Weather System (ITWS). The data are used to determine optimum routes for aircraft operating in and near the tenninal airspace. Data from other terminal area precipitation sensors such as the Terminal Doppler Weather Radar (TDWR) and the Next Generation Weather Radar (NEXRAD) are also used for this same purpose. The primary advantage of using the ASR-9 as a precipitation sensor is its high update rate, e.g. thirty seconds versus about five minutes for TDWR and N EX RAD. The ASR-9 is also quite reliable, with limited down time. Finally, range folding is not a significant problem with this radar. However, during ITWS prototype testing over the past three years, we have identified several limitations of using this radar as a precipitation sensor. For one, the maximum reflectivity of cells can be significantly underestimated by the ASR-9 due to partial filling of its fan-shaped elevation beam and cell-to-cell spatial averaging. Also, the occurrence of underestimation seems to increase when the radar operates in circular polarization mode. In addition, we have analyzed cases where significant precipitation-induced attenuation has occurred. Finally, because most ASR-9s are located on the airport, rain cores developing aloft, above the airport, maybe underestimated or missed entirely. This paper focuses on the problems identified through the ITWS prototype testing.
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Summary

The Airport Surveillance Radar (ASR-9) weather channel is an invaluable tool to air-traffic and flight management specialists. The precipitation data from this sensor is currently displayed on air-traffic specialists' radar scopes and is incorporated into the Integrated Terminal Weather System (ITWS). The data are used to determine optimum routes for...

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The capabilities and limitations of using the ASR-9 as a terminal area precipitation sensor

ASR-9 Weather Systems Processor (WSP): wind shear algorithms performance assessment

November 13, 1996
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Conference Paper
Author:
Joseph A. Cullen
…
Published in:
Workshop on Wind Shear and Wind Shear Alert Systems,. Oklahoma City, 13-15 November, 1996.
Topic:
aviation weather
R&D area:
R&D group:

Summary

Under Federal Aviation Administration sponsorship, Lincoln Laboratory has developed a prototype Airport Surveillance Radar Weather Systems Processor (ASR-WSP). This prototype has been used for field measurements and operational demonstrations since 1987. Measurements so acquired provide an extensive database for development and validation of the algorithms used by the WSP to generate operational wind shear information for Air Traffic Controllers. In this paper we assess the performance of the current versions of the WSP's microburst and gust front wind shear detection algorithms on data from each of the locations at which our prototype system has operated. Evaluation of the associated environmental characteristics (e.g., storm structure, radar ground clutter environment) allows for generalization of these results to the major U.S. climatic regimes where the production version of WSP will be deployed.
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Summary

Under Federal Aviation Administration sponsorship, Lincoln Laboratory has developed a prototype Airport Surveillance Radar Weather Systems Processor (ASR-WSP). This prototype has been used for field measurements and operational demonstrations since 1987. Measurements so acquired provide an extensive database for development and validation of the algorithms used by the WSP to...

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ASR-9 Weather Systems Processor (WSP): wind shear algorithms performance assessment

ASR-9 Weather System Processor (WSP): wind shear algorithms performance assessment

May 7, 1996
  |
Project Report
Author:
Mark E. Weber
…
Published in:
MIT Lincoln Laboratory Report ATC-247
Topic:
wind shear
R&D area:
R&D group:

Summary

Lincoln Laboratory has developed a prototype Airport Surveillance Radar Weather Systems Processor (ASR-WSP) that has been used for field measurements and operational demonstrations since 1987. Measurements acquired with this prototype provide an extensive data base for development and validation of the algorithms the WSP uses to generate operational wind shear information for Air Traffic Controllers. This report addresses the performance of the current versions of the WSP's microburst and gust front wind shear detection algorithms on available data from each of the WSP's operational sites. Evaluation of the associated environmental characteristics (e.g., storm structure, radar ground clutter environment) allows for generalization of results of the other major U.S. climatic regimes where the production version of WSP will be deployed.
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Summary

Lincoln Laboratory has developed a prototype Airport Surveillance Radar Weather Systems Processor (ASR-WSP) that has been used for field measurements and operational demonstrations since 1987. Measurements acquired with this prototype provide an extensive data base for development and validation of the algorithms the WSP uses to generate operational wind shear...

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ASR-9 Weather System Processor (WSP): wind shear algorithms performance assessment

Anomalous propagation ground clutter suppression with the Airport Surveillance Radar (ASR) Weather Systems Processor (WSP)

March 15, 1996
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Project Report
Author:
Joseph A. Cullen
Published in:
MIT Lincoln Laboratory Report ATC-244
Topic:
radar
R&D area:
R&D group:

Summary

Ground-clutter breakthrough caused by anomalous propagation (AP)--ducting of the radar beam when passing through significant atmospheric temperature and/or moisture gradients--is a significant issue for air traffic controllers who use Airport Surveillance Radar (ASR) weather channel data to guide aircraft through the airport terminal area. At present, these data are often contaminated with AP, leaving the controller unsure about the validity of information on storm location and intensity. The Weather System Processor (WSP), which is scheduled for deployment at 33 airports in the U.S., includes an AP-Editing algorithm designed to remove AP based on its Doppler-spectrum characteristics in ASR-9 data. This report provides a description of the algorithm currently used in the FAA/Lincoln Laboratory WSP prototype and a measurement of the performance of the algorithm during nine episodes of AP and/or true weather in Orlando, florida in 1991 and 1992.
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Summary

Ground-clutter breakthrough caused by anomalous propagation (AP)--ducting of the radar beam when passing through significant atmospheric temperature and/or moisture gradients--is a significant issue for air traffic controllers who use Airport Surveillance Radar (ASR) weather channel data to guide aircraft through the airport terminal area. At present, these data are often...

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Anomalous propagation ground clutter suppression with the Airport Surveillance Radar (ASR) Weather Systems Processor (WSP)

ASR-9 Microburst Detection Algorithm

October 22, 1993
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Project Report
Author:
Oliver J. Newell
…
Published in:
MIT Lincoln Laboratory Report ATC-197
Topic:
wind shear
R&D area:
R&D group:

Summary

The ASR-9 Wind Shear Processor (WSP) is intended as an economical alternative for those airports that have not been slated to receive a Terminal Doppler Weather Radar (TDWR) but have, or will be receiving, an ASR-9 radar. Lincoln Laboratory has developed a prototype ASR-9 WSP system which has been demonstrated during the summer months of the past three year in Orlando, Florida. During the operational test period, microburst and gust front warnings, as well as storm motion indications, were provided to the Air Traffic Control in real time. The ASR-9 Microburst Detection Algorithm (AMDA) is based on the earlier TDWR Microburst Detection Algorithm but has been substantially modified to match better the particular strengths and weaknesses of the ASR-9 rapid-scanning fan-beam radar. The most significant additions included a capability to detect overhead microbursts, a reflectivity processing step used to help detect velocity signatures that have been biased by overhanging precipitation, and a modification to some of the shear segment grouping and thresholding parameters to accommodate better the typical on-air siting of the ASR-9. In addition, the AMDA has been designed to be as efficient as possible to allow it to run at the radar's 4.8 seconds/scan antennas rotation rate on a single-board computer. A detailed description of AMDA, as well as the performance evaluation strategy and results, are presented in this report.
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Summary

The ASR-9 Wind Shear Processor (WSP) is intended as an economical alternative for those airports that have not been slated to receive a Terminal Doppler Weather Radar (TDWR) but have, or will be receiving, an ASR-9 radar. Lincoln Laboratory has developed a prototype ASR-9 WSP system which has been demonstrated...

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ASR-9 Microburst Detection Algorithm

Anomalous propagation associated with thunderstorm outflows

May 24, 1993
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Conference Paper
Author:
Mark E. Weber
…
Published in:
Proc. 26th Int. Conf. on Radar Meteorology, 24-28 May 1993, pp. 238-240.
Topic:
weather
R&D area:
R&D group:

Summary

Battan noted that ducting of radar energy by anomalous atmospheric refractive index profiles and resulting abnormally strong ground clutter can occur during three types of meteorological circumstance: (i) large scale boundary layer temperature inversions and associated sharp decrease in moisture with height -- these are often created by nocturnal radiative cooling; (ii) warm, dry air moving over cooler bodies of water, resulting in cooling and moistening of air in the lowest levels; (iii) cool, moist outflows from thunderclouds. In contrast to the first two types of anaomalous propagation (AP), radar ducting associated with thunderstorm outflows is quite dynamic and may mimic echoes from precipitating clouds in terms of spatial scale and temporal evolution. While non-coherent weather radars (e.g. WSR-57) are obviously susceptible to false storm indications from this phenomemenon, Doppler radars that select the level of ground clutter suppression based on "clear day maps" may also fail to suppress the AP-induced ground clutter echoes. Operational Doppler radar systems known to be susceptible to this phenomena are the National Weather Service's WSR-88D and the Federal Aviation Administration's Airport Surveillance Radar (ASR-9) six-level weather channel. In this paper, characteristics of thunderstorm outflow-generated AP are documented using data from a testbed ASR-9 operated at Orlando, Florida. The testbed radar's rapid temporal update (4.8 seconds per PPI scan) and accurate scan-to-scan registration of radar resolution cells enabled characterization of the spatial and temporal evolution of the AP-induced clutter echoes. We discuss implications of these phenomenological characteristics on operational systems, specifically the ASR-9. Algorithms for discrimination between true precipitation echoes and AP-induced ground clutter are discussed.
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Summary

Battan noted that ducting of radar energy by anomalous atmospheric refractive index profiles and resulting abnormally strong ground clutter can occur during three types of meteorological circumstance: (i) large scale boundary layer temperature inversions and associated sharp decrease in moisture with height -- these are often created by nocturnal radiative...

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Anomalous propagation associated with thunderstorm outflows

The 1990 Airport Surveillance Radar Wind Shear Processor (ASR-WSP) operational test at Orlando International Airport

July 17, 1991
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Project Report
Author:
Terri A. Noyes
…
Published in:
MIT Lincoln Laboratory Report ATC-178
Topic:
wind shear
R&D area:
R&D group:

Summary

Lincoln Laboratory, under sponsorship from the Federal Aviation Administration (FAA), is conducting a program to evaluate the capability of the newest Airport Surveillance Radars (ASR-9) to detect hazardous weather phenomena -- in particular, low-altitude wind shear created by thunderstorm-generated microbursts and gust fronts. The ASR-9 could provide coverage at airports not slated for a dedicated Terminal Doppler Weather Radar (TDWR) and could augment the TDWR at high-priority (high traffic volume, severe weather) facilities by providing a more rapid update of wind shear products, a better viewing angle for some runways, and redundancy in the event of a TDWR failure. An operational evaluation of a testbed ASR Wind Shear Processor (ASR-WSP) was conducted at the Orlando International Airport in Orlando, FL during August and September 1990. The ASR-WSP operational system issued five distinct products to Air Traffic Control: microburst detections, gust front detections, gust front movement predictions, precipitation reflectivity and storm motion. This document describes the operational system, the operational products, and the algorithms employed. An assessment of system performance is provided as one step in evaluating the operational utility of the ASR-WSP.
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Summary

Lincoln Laboratory, under sponsorship from the Federal Aviation Administration (FAA), is conducting a program to evaluate the capability of the newest Airport Surveillance Radars (ASR-9) to detect hazardous weather phenomena -- in particular, low-altitude wind shear created by thunderstorm-generated microbursts and gust fronts. The ASR-9 could provide coverage at airports...

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The 1990 Airport Surveillance Radar Wind Shear Processor (ASR-WSP) operational test at Orlando International Airport

Characteristics of thunderstorm-generated low altitude wind shear: a survey based on nationwide Terminal Doppler Weather Radar testbed measurements

December 1, 1990
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Conference Paper
Author:
Marilyn M. Wolfson
…
Published in:
Proc. 29th IEEE Conf. on Decision and Control, 5-7 December 1990, Vol. 2, pp. 682-688.
Topic:
aviation weather
R&D area:
R&D group:

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 in detection systems such as the associated reflectivity, surface wind shear, and temperature change are emphasized.
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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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Characteristics of thunderstorm-generated low altitude wind shear: a survey based on nationwide Terminal Doppler Weather Radar testbed measurements

Predicting summer microburst hazard from thunderstorm day statistics

October 22, 1990
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Conference Paper
Author:
Joseph A. Cullen
…
Published in:
16th Conf. on Severe Local Storms/Conf. on Atmospheric Electricity, 22-26 October 1990, pp. 383-387.
Topic:
aviation weather
R&D area:
R&D group:

Summary

Low-altitude wind shear, specifically, the aviation-hazardous form of wind shear known as the microburst, has been cited as the cause of several aviation disasters over the past two decades. Microbursts are strong, small-scale convective storm downdrafts that impact the ground and cause a violent divergent outflow of wind. The Federal Aviation Administration (FAA) recently awarded a contract for the production of 47 Terminal Doppler Weather Radars (TDWRs) to detect microbursts. Since the TDWR systems are expensive, only a limited number will be available for use at major U.S. airports. In deciding which airports will receive the TDWRs or any other advanced detection equipment, such as the ASR-9 with wind shear detection capability or the Enhanced Low Level Wind Shear Alert System, a detailed cost-benefit study will be performed. One factor that would aid in determining the benefit of advanced wind shear detection equipment is a knowledge of the average relative microburst threat at each major airport. Using "thunderstorm day" statistics and the results of measurements by the FAA TDWR testbed systems, we propose a method for predicting this threat.
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Summary

Low-altitude wind shear, specifically, the aviation-hazardous form of wind shear known as the microburst, has been cited as the cause of several aviation disasters over the past two decades. Microbursts are strong, small-scale convective storm downdrafts that impact the ground and cause a violent divergent outflow of wind. The Federal...

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Predicting summer microburst hazard from thunderstorm day statistics
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