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The COBEL model as part of a terminal-area ceiling & visibility (C&V) nowcast system: a progress report
July 18, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-241
Summary
The Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) is supporting the development of products aimed at providing automated guidance to the air traffic managers for the anticipation of changes in ceiling and visibility (C&V) conditions and wake vortex behavior in the terminal area. Fine-resolution, one-dimensional (column) numerical models are being considered to provide information on the evolution of the local fine-scale structure of the lower atmosphere over the terminal area. The Code Brouillard Eau Liquids (COBEL) column model is being investigated for potential use within the ITWS. This one-dimensional numerical model has been developed for the short-term prediction of fog events in the north of France. This report describes initial progress in adapting the COBEL model to a wider range of meteorological conditions. A parameterization of surface frost deposition was implemented and a slight error in the computation of stability in a saturated atmosphere was corrected. Tests suggest that these modifications represent important features of the newest version of the COBEL model. Other significant modifications to the COBEL model were performed. Pressure tendencies and vertical motion (vertical advection) were implemented as additional external forcings to the column model. Sensitivity tests show that these forcings play important roles in determining the onset, evolution and dissipation of low stratiform clouds. Some further applications of the model are briefly discussed and future development efforts are suggested.
Summary
The Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) is supporting the development of products aimed at providing automated guidance to the air traffic managers for the anticipation of changes in ceiling and visibility (C&V) conditions and wake vortex behavior in the terminal area. Fine-resolution, one-dimensional (column) numerical models...
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The Marine Stratus Initiative at San Francisco International Airport
June 25, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-252
Summary
San Francisco International Airport is one of the busiest airports in the United States and one of the highest delay airports in terms of total aircraft delay hours and number of imposed air traffic delay programs. As with most airports, weather is the primary cause of aircraft delay. In particular, the local airspace is prone to regular occurrences of low cloud ceiling conditions due to intrusion of marine air from the eastern Pacific Ocean from May through September. Typically, this layer of stratus clouds forms in the San Francisco Bay area overnight and dissipates during the middle to late morning. The timing of the stratus cloud dissipation is such that it frequently poses a threat to the morning arrival push of air traffic into San Francisco. Weather forecasters at the Central Weather Service Unit (CWSU) at the Oakland AirRoute Traffic Control Center are responsible for providing a forecast whether or not the cloudiness will impact morning traffic operations. This information is used for decision making by the Traffic Management Unit at Oakland Center in order to optimally match arriving traffic demand to available airport capacity. As part of the FAA's Integrated Terminal Weather System, the Weather Sensing Group at MIT Lincoln Laboratory has begun an effort entitled the "Marine Stratus Initiative." Its objective is to provide improved weather information and forecast guidance to the Oakland CWSU, which is responsible for providing weather forecasts to air traffic managers. During 1995, the main focus of the project was the design and implementation of a data acquisition, communication, and display infrastructure that provides forecasters with new sources of weather data and information. These initial capabilities were tested during an operational demonstration in August and September. As the project continues, the intent is to improve these new data sources and develop an automated or semi-automated algorithm that will process raw information to provide weather forecasters with numerical guidance to assist them in the forecast process. A description of airport operations at San Francisco and the impact of marine stratus are presented. An explanation is given of the marine stratus phenomenology and the primary factors contributing to cloud dissipation. This conceptual model of the dissipation process is used to define system requirements. A description of the hardware, communications, and display subsystems is provided. An overview of the 1995 demonstration, including user comments, is presented, as well as future plans for meeting the longer-term objectives of the project.
Summary
San Francisco International Airport is one of the busiest airports in the United States and one of the highest delay airports in terms of total aircraft delay hours and number of imposed air traffic delay programs. As with most airports, weather is the primary cause of aircraft delay. In particular...
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ASR-9 Weather System Processor (WSP): wind shear algorithms performance assessment
May 7, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-247
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.
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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Selected abstracts on aviation weather hazard research
January 2, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-242
Summary
This paper consists of bibliographic information and abstracts for literature on the topics of weather-related aviation hazards. These abstracts were selected from reports written for the ASR-9, ITWS, TDWR programs, sponsored by the Federal Aviation Administration (FAA), and the Wake Vortex program, sponsored by NASA Langley Research Center. All research was performed by MIT Lincoln Laboratory; some research was performed in collaboration with other organizations. These abstracts were compiled to allow participants in the ASR-9 program to conduct research related to their design, development, and production effort. The abstracts and bibliographic information were retrieved from several commercial databases (INSPEC, Ei Compendex*Plus, Aerospace Database, and NTIS) through an open literature search at the Lincoln Laboratory library. Sufficient information is included for readers to obtain documents of interest to them, but documents will not be provided directly by Lincoln Laboratory.
Summary
This paper consists of bibliographic information and abstracts for literature on the topics of weather-related aviation hazards. These abstracts were selected from reports written for the ASR-9, ITWS, TDWR programs, sponsored by the Federal Aviation Administration (FAA), and the Wake Vortex program, sponsored by NASA Langley Research Center. All research...
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Initial evaluation of terminal-area atmospheric vertical structure prediction algorithms using Fall 1994 ITWS/Wake Vortex Programs' meteorological data
November 6, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-237
Summary
A Dynamic Atmospheric Vertical Structure Nowcast System (DAVS-NS) is being developed that will add value to the Integrated Terminal Weather System (ITWS) by providing current and short-term forecasts of the vertical atmospheric structure focused at specific sites within the terminal domain. Operational applications of these estimates of the atmospheric vertical structure include predicting changes in airport operation rates due to ceiling and visibility (C&V) changes and in predicting wake vortex behavior. The core of this system would be a one-dimensional boundary layer column model. This report summarizes the evaluation of a modified Oregon State University (OSU) column model using data collected during the fall 1994 combined National Aeronautics and Space Administration (NASA) wake vortex project and the ITWS site operations at Memphis International Airport (MEM). Further efforts are necessary to develop and test an operational DAVS-NS prototype. The accuracy typically seen in column model predictions of the vertical temperature structure will limit errors in wake vortex dissipation rates to within a factor of two. Given the current working hypothesis for the San Francisco stratus burn-off phenomenon that rests largely on warming of the marine boundary layer by surface heat flux, the OSU model will also appear to be well suited for addressing this particular problem.
Summary
A Dynamic Atmospheric Vertical Structure Nowcast System (DAVS-NS) is being developed that will add value to the Integrated Terminal Weather System (ITWS) by providing current and short-term forecasts of the vertical atmospheric structure focused at specific sites within the terminal domain. Operational applications of these estimates of the atmospheric vertical...
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Terminal Weather Information for Pilots (TWIP) Test Report for 1994 Memphis and Orlando Demonstrations
April 28, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-227
Summary
Demonstrations of delivering the Terminal Weather Information for Pilots (TWIP) products to air carrier pilots via the Aircraft Communications Addressing and Reporting System (ACARS) data link were carried out at Memphis and Orlando during the summer of 1994. Six airlines participated in the demonstrations at both airports. The Terminal Weather Text Message and the Terminal Weather Character Graphics Depiction were evaluated using request/reply and forced update approaches. In the first case, the pilot needed to make a request in order to obtain the TWIP products. In the second case, the TWIP message was sent to the aircraft automatically when certain criteria were met (e.g., the aircraft was within 20 minutes of landing and wind shear alerts began at the airport). Five of the airlines used the request/reply approach, and one airline used the forced update approach. Pilot and contoller response to the TWIP products were evaluated using questionnaires. Statistics on message traffic and content were analyzed, and some cases were analyzed in detail to compare the TWIP products with the existing Surface Aviation Observation (SAO) reports. Recorded radio traffic also was analyzed to determine if there was any effect on the number of requests for terminal weather information. Pilots rated the TWIP products favorably, with most indicating that the messages provided improved situational awareness of terminal weather hazards without substantially increased cockpit workload. Controller reaction to the TWIP demonstration was generally neutral, indicating that providing these messages to pilots caused no substantial increase in contoller workload. Further results of the demonstration are discussed in the report, along with recommendations for subsequent TWIP demonstrations.
Summary
Demonstrations of delivering the Terminal Weather Information for Pilots (TWIP) products to air carrier pilots via the Aircraft Communications Addressing and Reporting System (ACARS) data link were carried out at Memphis and Orlando during the summer of 1994. Six airlines participated in the demonstrations at both airports. The Terminal Weather...
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Initial evaluation of the Oregon State University Planetary Boundary Layer Column Model for ITWS applications
April 13, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-233
Summary
The Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) is supporting the development of products important for air traffic control in the terminal area. Some ITWS is supporting the development of products important for air traffic control in the terminal area. Some ITWS products will allow air traffic managers to anticipate operationally significant short-term (0-30 min) changes in ceiling and visibility (C&V) and aircraft separations necessary to avoid encounters with wake vortices. Development of such products exploits data that will be available from new FAA terminal area sensor systems. These sensor systems include Terminal Doppler Weather Radar (TDWR), Next Generation Weather Radar (NEXRAD), the Meteorological Data Collection and Reporting System (MDCRS), and the Automated Surface Observing System (ASOS). A Dynamic Atmospheric Vertical Structure Nowcast System (DAVS-NS) is being developed that will add value to ITWS by providing current analyses and short-term forecasts of the vertical atmospheric structure focused at specific sites within the terminal domain. This report summarizes the initial evaluation of the Oregon State University one-dimensional boundary layer model for its potential role within a DAVS-NS.
Summary
The Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) is supporting the development of products important for air traffic control in the terminal area. Some ITWS is supporting the development of products important for air traffic control in the terminal area. Some ITWS products will allow air traffic managers...
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Integrated Terminal Weather System (ITWS) demonstration and validation operational test and evaluation
April 13, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-234
Summary
During summer 1994, MIT Lincoln Laboratory conducted the Operational Test and Evaluation Demonstration and Validation (Dem Val) of the Federal Aviation Administration's Integrated Terminal Weather System (ITWS). The purpose of the demonstration was to obtain user feedback on products and to prove that the ITWS products and concept were sufficiently mature to proceed with procurement. Dem Val was conducted at the Memphis International Airport from 23 May through 22 July and at the Orlando International Airport from 11 July through 19 August. Products were delivered to users at the Memphis Airport Traffic Control Tower (ATCT) and TRACON (Terminal Radar Approach Control), at the Memphis Air Route Traffic Control Center (ARTCC), at the Orlando International ATCT and TRACON, and at the Jacksonville ARTCC. In addition, ITWS displays were available to the National Weather Service forecast offices at Memphis, TN, and Melbourne, FL; to Northwest Airlines in Minneapolis, MN; and to Delta Airlines in Orlando, FL. This report documents the technical performance of the product generation algorithms. Each algorithm is described briefly, including the product operational and display concepts. The techniques by which the technical performance is assessed and the results of the assessment are presented. The performance of the algorithms is measured against the Minimum Operational Performance Requirements (MOPR), which products must meet to be considered operationally useful by the ATC user community.
Summary
During summer 1994, MIT Lincoln Laboratory conducted the Operational Test and Evaluation Demonstration and Validation (Dem Val) of the Federal Aviation Administration's Integrated Terminal Weather System (ITWS). The purpose of the demonstration was to obtain user feedback on products and to prove that the ITWS products and concept were sufficiently...
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The ITWS Runway Wind Nowcast Product
January 15, 1995
Conference Paper
Published in:
Sixth Conf. on Aviation Weather Systems, 15-20 January 1995, pp. 390-395.
Topic:
R&D area:
R&D group:
Summary
The Runway Wind Nowcast Product will support the ITWS objective by providing short term (up to 30 minutes) forecasts of the tailwind and crosswind components of the horizontal wind over each runway at an ITWS airport. These forecasts will enable FAA users to better anticipate wind shifts impacting runway usage and trajectories of approaching and departing air traffic. They may also support future ITWS products such ceiling and visibility nowcasts. Our initial development efforts, which are reported here, have been directed toward Orlando International Airport (MCO) as the product request originated there. However, in the near future we plan to expand the scope to include other ITWS airports including Memphis. The Runway Wind Nowcast Product is being developed to help Air Traffic Control (ATC) personnel answer the following question: Do we need to change runways? That would become necessary if tailwinds or crosswinds exceed usage thresholds. At most US airports, with dry runways, tailwinds much be less than five knots and crosswinds must be less than 15 knots. Other, lower thresholds apply if the runways are wet. However, these thresholds are subject to local modifications. For example, the MCO tailwind threshold for dry runways is 7 knots. The decision faced by ATC personnel seems, at first, to be clear cut: if the tailwind or crosswind exceeds nominal thresholds, use of that runway must be discontinued. The problem (at least at MCO) is that most threshold crossings are very brief. So, it may be better to temporarily hold traffic than to switch runways. Reliable (i.e., accurate and precise) short term forecasts will help ATC personnel make better hold-or-switch decisions.
Summary
The Runway Wind Nowcast Product will support the ITWS objective by providing short term (up to 30 minutes) forecasts of the tailwind and crosswind components of the horizontal wind over each runway at an ITWS airport. These forecasts will enable FAA users to better anticipate wind shifts impacting runway usage...
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TDWR scan strategy implementation
September 2, 1994
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-222
Summary
The Terminal Doppler Weather Radars (TDWRs) installed at major airports around the country are intended to enhance the safety of air travel by the detection and timely warning of hazardous wind shear conditions in the airport terminal area. To meet these objectives, scan strategies to efficiently cover the protected airspace were developed after extensive testing at several sites with different meteorological environments. Since the topology and geometry differ at each TDWR location, special considerations were necessary to define the specific scan sequences for each site. This report describes the criteria used to establish these scan sequences, including the determination of the lowest practicable elevation angle for each site - the "surface scan," which is used to detect microburst surface outflows, and other special scans such as the "MTS scan," which is used to illuminate the remote Moving Target Simulator (MTS).
Summary
The Terminal Doppler Weather Radars (TDWRs) installed at major airports around the country are intended to enhance the safety of air travel by the detection and timely warning of hazardous wind shear conditions in the airport terminal area. To meet these objectives, scan strategies to efficiently cover the protected airspace...
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