Download or read book Thunderstorm Turbulence Hazard Detection written by R. K. Crane and published by . This book was released on 1980 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report documents the development and testing of a viable aircraft hazard detection scheme which operates as well employing conventional radar data as it does employing Doppler radar data. The detection scheme was evaluated using aircraft penetrations into the most turbulent regions of hail storms. These regions are of interest when verifying that turbulence can be detected but are not optimum for evaluating the detection technique under realistic operating conditions. If, in the latter case, higher false alarm rates can be expected, more development will be necessary to utilize more effectively the available information before the hazard detection procedure can be incorporated into an air traffic control environment. The recommended program to develop the automatic hazard detection system include: refine the cell and cluster detection algorithms to reduce the effect of the statistical uncertainties in the estimation of velocity perturbations; refine the cell significance algorithms using cell age location in the development pattern, apparent vertical transport of horizontal momentum and similar parameters to provide and indication of the intensity of the turbulence; and develop a graphical display of the cell, cluster and contour data that can be provided both to meteorologists for the development of short range forecasts.
Download or read book Radar Detection of Thunderstorm Hazards for Air Traffic Control Volume I Storm Cell Detection written by Robert K. Crane and published by . This book was released on 1976 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: A procedure was developed to detect hazardous regions within thunderstorms using weather radar data. The procedure is based upon the hypothesis that convective turbulence occurs within 2-3 km of relative radar reflectivity maxima (cells). The hypothesis was tested using a limited set of simultaneous aircraft radar data. Good agreement was found between the observed regions of convective turbulence and the cell locations determined by radar. The viability of the hazard detection hypothesis as a basis for automatic warning and forecast depends upon the reliability of the cell detection and tracking algorithms. Analysis of precision radar data revealed that the cells are small in area extent, have a detection probability in excess of 0.9 using multiple radar scans, and are readily tracked for periods between 10 and 20 minutes. The characteristics of radar systems for acquiring data to support cell detection, are discussed. The role of Doppler spectral data is explored, and it is found that practical limitations on radar beamwidth hamper direct observation of turbulence on the scale size hazardous to aircraft. (Author).
Download or read book Radar Detection of Turbulence in Thunderstorms written by Alan R. Bohne and published by . This book was released on 1981 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical investigations are undertaken to relate intensity of turbulent air motion to Doppler radar spectrum mean and variance in precipitation environments. Examples of theoretical radar derived turbulence power density spectra and total precipitation motion variance show that effects due to imperfect particle response are significant for turbulence scale lengths less than 250 m. Doppler spectrum variance and estimated eddy dissipation rate (epsilon) are found strongly dependent upon precipitation environment for ranges less than about 20 km, and for cases where the turbulence outer scale length (lambda) is less than 0.5 km. They are also found to be essentially independent of lambda when the maximum pulse volume dimension is less than 1/2 lambda, and independent of range but strongly dependent on lambda at ranges where the maximum pulse volume dimension is greater than lambda. Estimation of epsilon by radar is shown to be unreliable until a method of remotely determining lambda is found. Nevertheless, classification of turbulence severity (index = cube root of epsilon is possible with only a reasonable guess of lambda. Analyses of aircraft/gust velocity data indicate that thunderstorm turbulence is localized into discrete patches, and that such localization must be accounted for when aircraft gust velocity data undergo power spectrum analysis.
Download or read book Radar Detection of Thunderstorm Hazards for Air Traffic Control Volume II Radar Systems written by S. M. Sussman and published by . This book was released on 1976 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radar systems are investigated for the acquisition of weather data to support detection and forecasting of hazardous turbulence assoicated with individual storm cells. Utilization of the FAA Airport Surveillance Radar (ASR) is explored. The issues of antenna polarization and Sensitivity Time Control (STC) that impact on shared operation for aircraft and weather detection are addressed. Candidate system configurations employing a common RF channel and dual orthogonal polarization channels are discussed. Ground clutter discrimination by coherent Doppler and noncoherent (Doppler spread) processing methods is described. An interim procedure is suggested for obtaining fixed reflectivity contour data from a Moving Target Detector for use in the all-digital ARTS. A preliminary design is presented for a new joint-use, long-range weather radar to support enroute air traffic controllers and to meet the data requirements of the National Weather Service and the Air Weather Service. (Author).
Download or read book Aviation Turbulence written by Robert Sharman and published by Springer. This book was released on 2016-06-27 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anyone who has experienced turbulence in flight knows that it is usually not pleasant, and may wonder why this is so difficult to avoid. The book includes papers by various aviation turbulence researchers and provides background into the nature and causes of atmospheric turbulence that affect aircraft motion, and contains surveys of the latest techniques for remote and in situ sensing and forecasting of the turbulence phenomenon. It provides updates on the state-of-the-art research since earlier studies in the 1960s on clear-air turbulence, explains recent new understanding into turbulence generation by thunderstorms, and summarizes future challenges in turbulence prediction and avoidance.
Download or read book Radar Detection of Turbulence in Thunderstorms written by Alan R. Bohne and published by . This book was released on 1981 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical investigations are undertaken to relate intensity of turbulent air motion to Doppler radar spectrum mean and variance in precipitation environments. Examples of theoretical radar derived turbulence power density spectra and total precipitation motion variance show that effects due to imperfect particle response are significant for turbulence scale lengths less than 250 m. Doppler spectrum variance and estimated eddy dissipation rate (epsilon) are found strongly dependent upon precipitation environment for ranges less than about 20 km, and for cases where the turbulence outer scale length (lambda) is less than 0.5 km. They are also found to be essentially independent of lambda when the maximum pulse volume dimension is less than 1/2 lambda, and independent of range but strongly dependent on lambda at ranges where the maximum pulse volume dimension is greater than lambda. Estimation of epsilon by radar is shown to be unreliable until a method of remotely determining lambda is found. Nevertheless, classification of turbulence severity (index = cube root of epsilon is possible with only a reasonable guess of lambda. Analyses of aircraft/gust velocity data indicate that thunderstorm turbulence is localized into discrete patches, and that such localization must be accounted for when aircraft gust velocity data undergo power spectrum analysis.
Download or read book Weather Hazards to Aircraft written by Source Wikipedia and published by Booksllc.Net. This book was released on 2013-09 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 29. Chapters: Air-mass thunderstorm, Atmospheric icing, Carburetor icing, Clear-air turbulence, Cloud suck, Downburst, Fog, Icing conditions, Microburst, Wind gradient, Wind shear. Excerpt: A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm, is a form of turbulent weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the thunderstorm is the cumulonimbus. Thunderstorms are usually accompanied by strong winds, heavy rain and sometimes snow, sleet, hail, or no precipitation at all. Those that cause hail to fall are called hailstorms. Thunderstorms may line up in a series or rainband, known as a squall line. Strong or severe thunderstorms may rotate, known as supercells. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear causes a deviation in their course at a right angle to the wind shear direction. Thunderstorms result from the rapid upward movement of warm, moist air. They can occur inside warm, moist air masses and at fronts. As the warm, moist air moves upward, it cools, condenses, and forms cumulonimbus clouds that can reach heights of over 20 km (12.45 miles). As the rising air reaches its dew point, water droplets and ice form and begin falling the long distance through the clouds towards the Earth's surface. As the droplets fall, they collide with other droplets and become larger. The falling droplets create a downdraft of air that spreads out at the Earth's surface and causes strong winds associated commonly with thunderstorms. Thunderstorms can generally form and develop in any particular geographic location, perhaps most frequently within areas located at mid-latitude when...
Download or read book Air Turbulence and its Methods of Detection written by Leonardo Di G. Sigalotti and published by CRC Press. This book was released on 2023-02-24 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is a concise guide dealing with the subject of air turbulence and its methods of detection with particular applications to aviation turbulence. It begins with a general description of turbulence and provides a background into the nature and causes of atmospheric turbulence that affect aircraft motion, giving updates on the state-of-the-art research on clear air turbulence (CAT). Important physical processes leading to the Kelvin-Helmholtz instability, a primary producer of CAT, are also explained. The several categories of CAT along with its impact on commercial aviation are also presented in a separate chapter, with particular emphasis on the structural damages to planes and injuries. The central theme of the book deals with both the earlier and the latest CAT detecting methods and techniques for remote and in situ sensing and forecasting. A concise presentation of new technologies for reducing aviation weather-related accidents is also offered. A chapter on the weather accident prevention project of the NASA aviation safety program is also included. Additionally, the book ends with a full description of the recent research activities on CAT and future challenges in turbulence detection, prediction and avoidance.
Download or read book Test and evaluation of the radar thunderstorm turbulence detection system written by and published by . This book was released on 1982 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A thunderstorm turbulence detection test bed was developed at the Federal Aviation Administration (FAA) Technical Center by the Massachusetts Institute of Technology, Lincoln Laboratory. This consists of a system to measure and process Doppler radar parameters, and an FAA aircraft instrumented to measure turbulence concurrently with the radar observations. The test bed is being used to investigate the relationship between radar-and aircraft-measured turbulence. Radar measurements of the Doppler spectrum width and aircraft measurements of airspeed fluctuations and center-of-gravity normal accelerations were converted to the cube root of epsilon (cube root of the turbulence dissipation factor) for comparison. Several data collections were made during the summer of 1980. Results of data analysis showed that the major turbulence sequences experienced by the aircraft were essentially reflected by the radar. However, Linear correlation coefficients between radar and aircraft the the cube root of epsilon were only about 0.5. The low correlations are considered to be due to differences in response to turbulence by the two measuring systems, deficiencies in the radar processing, and radar data interpolation errors between the 80-second radar scans. In a more practical analysis, radar-measured turbulence, classified into ranges of light, moderate, and severe turbulence, showed a potentially useful relationship to aircraft turbulence. The predictive value was enhanced by consideration of radar reflectivity factor as a screening variable.
Download or read book Thunderstorms a Social Scientific Technological Documentary Instruments and techniques for thunderstorm observation and analysis written by and published by . This book was released on 1982 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multi Hazard Identification and Risk Assessment written by and published by . This book was released on 1997 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence and Radar Photographic Studies of Thunderstorms written by United States. Air Force. Wright Air Development Division and published by . This book was released on 1961 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Instruments and Techniques for Thunderstorm Observation and Analysis written by and published by . This book was released on 1982 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aviation Weather for Pilots and Flight Operations Personnel written by United States. Federal Aviation Administration and published by . This book was released on 1975 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Evaluation of the Use of Ground Radar for Avoiding Severe Turbulence Associated with Thunderstorms written by J. K. Thompson and published by . This book was released on 1949 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analysis of data obtained from the 1947 Ohio operations of the U.S. Weather Bureau thunderstorm project indicates that the magnitude and intensity of gusts encountered in air-mass and frontal thunderstorms may be considerably reduced by avoiding storm areas indicated by ground radar of a 10-centimeter wavelength. The analysis also indicates that the ground radar used becomes more effective for turbulence avoidance as the flight altitude is increased up to 25,000 feet and is least effective at 6,000 feet.
Download or read book An Evaluation of an Automatic Cell Detection and Tracking Algorithm written by James G. Wieler and published by . This book was released on 1982 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: A storm tracking algorithm designed to detect and track fine structure in digitized radar data is evaluated. These fine structures are defined by regions containing values within 3 dB of peaks in reflectivity factor. The algorithm describes storm structure and evolution by correlating these peak regions in time and space. The evaluation consists of a comparison of the algorithm output with raw data and with output from an AFGL algorithm which detects and tracks three-dimensional reflectivity weighted centroids defined by a preselected threshold. It is concluded that the algorithm cannot reliably detect and track significant structures within storms when applied to data sets with a temporal resolution of aprox. 6 min and a spatial resolution of 1.0 deg in azimuth and 0.7 deg in elevation. The significance of tracking 3 dB peaks is questioned and the implication of defining a larger peak threshold is discussed. The algorithm does track the large features of storms with results similar to the AFGL algorithm. However, it does not run in real time and is not modular, unlike the AFGL algorithm.
Download or read book Aircraft Turbulence Detection and Display from the Professional Pilot s Perspective written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study was to investigate the detection and display of weather avoidance information to commercial airline, business aircraft, and general aviation aircraft cockpits from the perspective of the professional pilot. A flight campaign was conducted over a period of three years. Convective weather detection was attempted utilizing an experimental airborne weather radar installed on NASA's Airborne Research Integrated Experiments Systems (ARIES) Boeing 757. Additionally ground-based Next Generation Radar (NEXRAD) information and textual data was linked to the aircraft for correlation. It was determined after encountering several heavy turbulence events that radar detection and conventional displays alone were inadequate to provide the types of data needed by the professional flight crew in order to make informed decisions concerning weather avoidance. The NASA King Air B200 and Cessna 206 were also used to evaluate the human factors issues concerning cockpit displays for these classes of aircraft, which are also flown by some professional pilots. In addition to convective weather avoidance associated with thunderstorms or frontal activity, the study also explored clear air turbulence detection techniques. The detection of these events and the communication of this information to other aircraft in an automated Pilot Report format are being used to display danger areas to other pilots.
