Developing a model for horizontal array coherence in the presence of random linear internal waves

Abstract

The resolution of a horizontal array in shallow water is limited by the environmental variability introduced by several oceanographic processes. The present work exercises a numerical model for how one oceanographic process, nearly linear internal waves, affects array coherence. As the linear internal waves can be represented as a random process, the model is statistical and calculates the mean coherence length. Three results from William Carey's pioneering work [J. Acoust. Soc. Am., vol. 104, pp. 831–837, 1998] are examined: an analytical model for the array correlation function, the weak dependence of coherence length on source-receiver range, and scenarios where linear internal waves can produce a coherence length of approximately 30 wavelengths.