The acoustic propagation in the inhomogeneous ocean with the current

The problem of acoustic propagation in the inhomogeneous ocean with the current is investigated. The characteristics of the ocean vary slowly in horizontal direction. The solution is obtained in the form of the series on powers of small parameter $\varepsilon$, where $\varepsilon=v_0c_0^{-1}$, $v_0=\max|\vec v|$, $\vec v$ – velocity of the current, $c_0$ – adiabatic velocity of the sound. The space-time ray method is used for determination of the coefficients of the series.