Аннотация:The effect of a gas-saturated layer in the bottom on the formation of an acoustic field from an air source in the water layer of shallow water is numerically studied. The analysis of the scalar-vector structure of an acoustic field in waveguides with different parameters shows that an interferential acoustic field structure, whose character depends on the presence of a gas-saturated layer on the bottom, is formed in the presence of a air sound source in the water layer at low frequencies. The interferential structure contains a sequence of local minima, in which acoustic power flux vortices with a spatial distribution governed by waveguide parameters are observed. On the one hand, this limits the possibilities of restoring the elevation angle of an air source when measuring the acoustic field in the water layer in the case of an unknown bottom. On the other hand, this opens opportunities of estimating the bottom parameters by analyzing the scalar-vector structure of the acoustic field formed in the water layer by a controllable air source.