Numerical simulation of transverse current monitoring in the Fram Strait

The horizontal refraction method (HRM) of transverse current acoustics moni toring in the Fram Strait environment is modeled numerically. The current p rofile was constructed on the basis of experimental data on the West Spitsb ergen Current (WSC) structure and the complex environment of the region pre sented by the sound speed profiles, which were derived from the experiments . The HRM is based on the measurements of the deflection of the horizontal modal rays due to the gradient of the refraction index produced by the tran sverse current. The signals received by the antennas in a receiving plane p erpendicular to the propagation axis have a modal phase difference in propo rtion to the average transverse velocity, which is due to the different ori entation of the acoustical path of the current. The interesting result is t hat even in a strong mode coupling environment the numerically obtained pha se difference is quite close to its value as calculated by adiabatic approx imation. The physical reason behind this is most likely that the mode coupl ing impact can be canceled at the sound signal propagation along the two ve ry close paths.