Flight Data Analysis of the Relationship Between Atmospheric Temperature Change and Clear Air Turbulence

摘要

Certain atmospheric temperature changes have been observed to be a factor in detecting the occurrence of clear air turbulence, especially at jet altitudes above 25,000 feet. Data for this study were collected on 146 flights during the year while riding as an extra crew member in the cockpit of airline and military jet aircraft. An aircraft flight data recorder which was modified to collect static air temperature information, provided another valuable source of research data. The study concentrated on investigating the validity of the theory that temperature gradients may be used to indicate clear air turbulence. A comparison between several rates of temperature change was made in an effort to determine which would indicate actual flight conditions most efficiently. From flight observations using a portable test instrument to detect temperature changes and the flight recorder data, a rate of temperature change of 1.0C per minute was found to be the most useful criterion for correctly indicating flight conditions in the majority of cases. The aircraft instrumentation in the research program included a portable test instrument as well as the normal components of an air data system and temperature sensors. The flight recorder and air data system on one DC-8 were modified to collect static air temperature information on the flight data recorder using an improved temperature sensor. In addition, a vertical acceleration indicator located on the cockpit instrument panel provided an instantaneous objective measurement of turbulence intensity on this DC-8. (Author)