A multifrequency scintillation method for ocean flow measurement

The transverse flow of inhomogeneous fluid produces fluctuation of the acou stic signal passing through it. The coherence of frequency-spaced signal fl uctuation is related to the advection of the inhomogeneous medium through t he sound path, thus providing a basis for the current velocity measurement. This method can be considered to be the "frequency-domain" version of the conventional scintillation approach to the current velocity registration ba sed on the measurement of the signal correlation transmitted from the sourc e to the two separated in space receivers (space-domain scintillation) [S. Clifford and D. Farmer, J. Acoust. Sec. AM. 74, 1826-1832 (1983)]. The sens itivity of the method depends on the features of the ocean fine structure, which is determined mainly by the internal waves and turbulence To estimate the sensitivity of the multifrequency method of transverse current probing , the coherence function of two signals propagating through a frozen and mo ving internal wave held and through the turbulence is considered. The appli cation of the multifrequency signal allows estimation of the fine-structure parameters as well as the current velocity. (C) 2001 Acoustical Society of America.