Air Turbulence and its Methods of Detection
Air Turbulence and its Methods of Detection

Author: Leonardo Di G. Sigalotti

Publisher: CRC Press

Published: 2023-02-24

Total Pages: 429

ISBN-13: 1000844234

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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.

Aviation Turbulence
Aviation Turbulence

Author: Robert Sharman

Publisher: Springer

Published: 2016-06-27

Total Pages: 529

ISBN-13: 331923630X

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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.

Study of Techniques for Detection and Measurement of Clear Air Turbulence
Study of Techniques for Detection and Measurement of Clear Air Turbulence

Author: Raymond E Zirkle (Jr)

Publisher:

Published: 1966

Total Pages: 135

ISBN-13:

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Two general ways in which laser optical radar (optar) might be useful for clear air turbulence detection were examined. The first method involves spectral analysis of doppler-shifted light, backscattered by moving particles, to provide measures of average and gust spectrum velocity components. The second method involves the mapping of particle formations arrayed in the atmosphere by correlates of rough flying conditions such as wind shear, the jet stream, mountain waves, etc. Calculations show that the particulate matter of the troposphere which dominates optical backscatter is dynamically suitable for the mapping of wind motions consistent with anticipated requirements of CAT detection. Experiments by other groups have shown that laser doppler methods can measure particle velocities in the laboratory. Experimental extensions of these techniques will be needed to apply the concept to aircraft. An experimental program with pulsed ruby laser optars was conducted. Particle arrays were detected in both laboratory and field environments, but no evidence was obtained indicating a correlation with turbulent conditions. Laboratory turbulence-generated refractive index changes were much higher than those encountered in the atmosphere. Field tests at Rollinsville, Colorado were inconclusive due to poor weather conditions. Many cloud returns were obtained, but they were not related to mountain waves or turbulence. Airborne optars should be used in further work of this type to provide mobility and to allow direct correlation between signals received and turbulence encountered. (Author).

Evaluation of Clear Air Turbulence Detection by Ground-based Radars, Special Rawinsondes, and Aircraft, 1967-1971
Evaluation of Clear Air Turbulence Detection by Ground-based Radars, Special Rawinsondes, and Aircraft, 1967-1971

Author: Roland J. Boucher

Publisher:

Published: 1974

Total Pages: 108

ISBN-13:

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During the winter operations, from 1967 to 1971, of Clear Air Turbulence (CAT) research at Wallops Island, Virginia, the Weater Radar Branch of Air Force Cambridge Research Laboratories observed eighteen cases of significant turbulence, defined as cases of light-to-moderate or moderate intensity. The report presents the meteorological data for each of these cases, consisting of synoptic sea level and upper air charts and rawinsonde data, observations of clear air echoes with powerful radars, and aircraft data which are used to indicate the present location and intensity of the turbulence.

In-flight Turbulence Detection
In-flight Turbulence Detection

Author: Alan R. Bohne

Publisher:

Published: 1985

Total Pages: 68

ISBN-13:

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A limited set of radar and aircraft data acquired during the 1981 and 1982 Joint Agency Turbulence Experiment are used to compare incoherent and coherent radar methods for atmospheric turbulence severity estimation. Time series of ground-based radar in-phase and quadrature signal return data are processed by Doppler (Fast fourier tranform) and incoherent (R-meter with and without noise correction) methods to determine Doppler spectrum variance. These variance data serve as input to a turbulence algorithm to derive estimates of turbulence severity. Theses estimates are then compared with in-situ aircraft measurements. Results show the order of preference for the radar methods is Dopple, R-meter with noise correction, and R-meter without noise correction. The Doppler, R-meter with noise correction, and R-meter without noise correction. The R-meter without noise correction method must be considered unreliable since it results in large overestimates of turbulence severity when the signal to noise ratio is less than about 12 dB. The R-meter with noise correction, and R-meter with noise correction method generally duplicates well the results derived from Doppler analysis and may be considered a reasonable alternative when Doppler capability is not available. Keywords: Incoherent radar; Doppler radar; R-meter; Turbulence severity; Eddy dissipation rate; Composite severity class.