Acoustic sounding—A new approach to the study of atmospheric structure

Abstract

Short pulses of acoustic energy at a carrier frequency of 950 Hz were beamed upwards from an array of loudspeakers. The energy which was backscattered from the random fluctuations of temperature within the turbulent regions of the lower 300 meters of the atmosphere was received on the same array and recorded on a facsimile receiver. The acoustic echoes were calibrated against temperature and wind data obtained from sensing elements fitted on a tower 75 meters high, 500 meters away from. the acoustic sounder. Sounding records, together with temperature and wind data, are presented for thermal plumes, breaking waves, and the formation and breakup of a radiation inversion. The usefulness of the acoustic sounding technique in continuously monitoring the intensity of small-scale temperature inhomogeneities in the lower atmosphere is emphasized. Future developments are outlined.