Spatial correlation is an important characteristic parameter in underwater acoustics. Much attention has been paid to the horizontal correlation.

Generally, the transverse correlation is dominated by the randomness of the waveguide. However, researches on transverse correlation are rare, so ZHANG Yanjun, ZHANG Renhe and LI Fenghua of National Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences performed a shallow water acoustic experiment in the Yellow Sea and tried to get the relationship between transverse correlation coefficient and frequency.

In the 3-year long study, the researchers observe that the transverse correlation coefficient is an oscillation function of frequency. They develop a model based on adiabatic normal mode theory in a random inhomogeneous waveguide which is statistically isotropic in a horizontal plane. Through repeated verification, they get the indication that with the weak fluctuation approximation, the transverse correlation coefficient and frequency have the relationship of, which is supported by the measured data.

More detailed information can be found in CHIN. PHYS. LETT. (Vol. 27, No. 8, 2010, 084301).