In this paper, we study the effects of multiple scattering of the noise-field modes from the perturbed sea surface. An approximate analytical solution of the transfer equation is obtained for the intensity of the noise-field modes. This phenomenon is numerically simulated for the winter and summer hydrologies typical of the Barents Sea conditions. It is shown that the mode-scattering influence on the character of the energy mode spectrum of dynamic noise in shallow sea is not only quantitative, but also qualitative in some cases. Comparing the results of numerical analysis and the proposed solution, we see that the modal spectrum of dynamic noise is predicted by this solution with sufficiently high accuracy under conditions typical of shallow sea for small and moderate wind velocities.