Scattering of Sound Used to Study the Atmospheric Boundary Layer

We are using the scattering of sound for the remote sensing of thermal turbulence in the atmosphere. Over the past several years an acoustic radar has been developed and operated at the University of Toronto to study the planetary boundary layer. We were one of the first groups to operate successfully in a noisy urban environment. A brief outline of the concept and technique of acoustic echo sounding will be given along with a discussion of some of our observations. In the past, the study of the planetary boundary layer (50 m — 1 km) of the atmosphere has been limited by the lack of access with direct access being limited to occasional baloon ascents or airplane traverses and in a few cases, to instrumented towers extending beyond 100 m. Recent advances in remote sensing techniques now allow us to remotely monitor parameters of the boundary layer on a continuous real time basis. Acoustic radar, FM-CW radar and lidar (laser radar) are the three techniques being most actively investigated and applied.