An Airborne Laser Air Motion Sensing System. Part II: Design Criteria and Measurement Possibilities

Abstract

A conically scanning Doppler lidar technique for measuring air motions from an aircraft is proposed in the companion paper (Keeler et al.). A theoretical analysis of this technique shows that, assuming isotropic turbulence, the technique is feasible for measuring air motions to woes small enough that the velocity spectra in a convective atmospheric boundary layer can be resolved well into the inertial subrange, and most of the turbulent motions that contribute to the vertical fluxes can be resolved. A scanning beam range of 10 m was selected to ensure that flow distortion induced by the aircraft will not significantly affect the velocity measurement. Thus, the technique offers improved accuracy over presently used immersion air motion sensors. An additional feature is the possibility of measuring mean vertical wind shear.