Publications

Models of vortex behavior as a function of atmospheric conditions are being developed in an attempt to improve safety and minimize unnecessary airport capacity restrictions due to wake vortices. Direct measurements of vortices and the relevant meteorological conditions in an operational setting, which would serve to improve the understanding of vortex behavior, are scarce and incomplete. A comprehensive vortex, meteorological, and aircraft measurement system has been constructed at Memphis International Airport and operated in two I-month periods during 1994 and 1995. A 10.6 um continuous-wave (CW) coherent lidar was used to measure vortex parameters with high fidelity. This lidar features a number of improvements over previous systems, including an automatic vortex detection and tracking algorithm to ensure efficient scanning. Meteorological data were collected from a 45 m instrumented tower, balloon soundings, a wind profiler/radio acoustic sounding system (RASS), sonic detection and ranging (SO DAR), and other sensors. This paper presents ensemble distributions of the conditions under which the over 500 aircraft were measured, and samples of vortex and atmospheric measurements. These data will be compared with theoretical predictions of vortex behavior as part of the development of an operational system designed to reduce aircraft spacings in the terminal area.

This paper describes wake vortex field measurements conducted during August, 1995 at Memphis, TN. The objective of this effort was to record wake vortex behavior for varying atmospheric conditions and aircraft types. Wake vortex behavior was observed using a mobile CW coherent lidar. This lidar features a number of improvements over previous systems, including the first-ever demonstration of an automatic wake vortex detection and tracking algorithm. An extensive meteorological data collection system was deployed in support of the wake vortex measurements, including a 150-ft instrumented tower, wind profiler/RASS (radio acoustic sounding system), sonar and balloon soundings. Aircraft flight plan and beacon data were automatically collected to determine aircraft flight number, type, speed, and descent rate. Additional data was received from airlines in postprocessing to determine aircraft weight and model. Preliminary results from the field measurement program are presented illustrating differences in wake vortex behavior depending on atmospheric conditions and aircraft type.

A CW-coherent laser radar using a 20-Watt CO2 laser has been constructed and deployed for the measurement of wake-vortext turbulence. This is part of a larger effort to understand the motion and decay of wake vortices as a function of the local atmospheric conditions. The construction and operation of the lidar and the initial fielding at Memphis International Airport are described.