As known from in situ observations, inhomogeneities of flows and of the atmospheric boundary layer produce variations of the intensity of wind wave breaking. A relevant phenomenological model is suggested here, describing in situ data on the breaking of waves in the presence of internal waves. The response of the wave breaking to the flow's inhomogeneity enhances with the growth of its spatial or temporal scale. For the mesoscale (10-100 km) inhomogeneities, the model is essentially simplified - wave breakings depict the local energy inputs to wind waves.