Evaluation of boundary layer remote sensors at airport environments

There has been a renewed interest in the application of remote sensor technology to operational aviation and airport-related activities such as the NASA Aircraft Vortex Spacing System (AVOSS). Vertical profiles of winds, temperature and turbulence are needed to determine wake vortex behavior. During field experiments at both Memphis International Airport, and Dallas-Fort Worth Airport since 1994, a variety of insitu and remote sensors have been used to provide these vertical profiles. Radio Acoustic Sounding Systems (RASS), Doppler-acoustic sodars, a UHF profiler and lidars have many advantages in measuring wind and temperature profiles in the lower atmospheric boundary layer since they can operate more or less continuously and unattended; however, there are limitations in their operational use at airports. For example, profilers deteriorate (limited altitude coverage or missing) in moderate or greater rain and can be affected by airplane targets in their field of view. Sodars are less affected by precipitation, but are influenced by the high noise environments of airports and strong winds. Morning temperature inversions typically limit performance of RASS, sodars and profilers. Fog affects sonic anemometers used for turbulence assessments near the ground. Lidars can have difficulties in clouds, fog or heavy precipitation. Operational capabilities and limitations of these and other sensors used in the AVOSS program are discussed, and performance during an extended period is illustrated with examples from sensors measuring the same parameter at the same time. Despite their limitations these sensors have proven useful to provide wind and temperature profiles for AVOSS.