Acoustic scintillations and angle-of-arrival fluctuations observed outdoors with a large planar vertical microphone array

A vertical planar array of 32 microphones (eight elements in the vertical d irection and four in the horizontal; overall dimensions approximately 6 m b y 3 m) was used to image the scintillations and angle-of-arrival fluctuatio ns from a source 770 m distant. Data sets of 20-min duration were collected in a variety atmospheric conditions. On a windy afternoon, the source imag e underwent dramatic scintillations and fluctuations in its apparent positi on. For still nighttime conditions, the image was much more stable, althoug h deep fading still occurred. (C)1999 Acoustical Society of America.