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.

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.

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.

This publication is divided into two sections: detection of clear air turbulence; and operational aspects. Partial contents include: clear air turbulence problems and solutions a state-of-the-art report; the feasibility of optical radar to detect clear air turbulence; early warning of clear air turbulence by photometric measurements; analysis of clear air turbulence incidents and much more.

Turbulence due to vertical wind shear at the tropopause temperature inversion produces small-scale temperature irregularities which cause echoes on sensitive microwave radars and allow monitoring of the tropopause level and study of the progression of dynamic instability and turbulence generation in the clear atmosphere. For tropopause temperatures below about -45 to -50°C, the structure constant C2T, a characteristic measure of temperature variability within the inertial subrange, may be determined from radar reflectivity with an error less than 3 dB by neglecting water vapor contributions to refractive-index variability.