The paper presents some of the aspects of influence of a subsurface bubble layer on the acoustical signals accompanying an act of water drops falling onto water surface. Laboratory drop-tests were conducted using aerated and degassed seawater and freshwater in presence of surface-active substances. Comparisons between different data series imply that initial drop impact pressures and new bubble generation rates are influenced mainly by the existence of subsurface bubble layer and are less sensitive to changes in surface tension. The statistical relationships between noise spectra created by drop splashes, average bubble creation rates and drop parameters under different conditions are presented. The results clearly indicated that the laboratory observed changes of noise intensity due to presence of gas bubbles in water should be taken into account when interpreting rainfall noise level at higher wind conditions in the sea.
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