Angle of arrival fluctuations are one manifestation of acoustic propag
ation through a turbulent flow. Here the two-dimensional angle of arri
val distribution for a 670-m acoustic path through a high Reynolds num
ber flow in a tidal channel is examined and its origin and relationshi
p to the flow field is determined. Over scales greater than the variab
ility due to turbulence, a solution of the ray propagation equation ex
plains the effect of advection on the horizontal arrival angle. The ra
pidly fluctuating two-dimensional angle of arrival distribution shows
a degree of scatter consistent with the level of turbulent intensity.
After removal of effects due to the finite aperture, orthogonal compon
ents are correlated during strongly sheared flow implying that the tur
bulence is weakly anisotropic over the measured scales. This anisotrop
y is discussed in terms of the cross stream velocity gradients partial
derivative v/partial derivative x' and partial derivative v/partial d
erivative z', where (x',z') are perpendicular diagonal coordinates. (C
) 1996 Acoustical Society of America.