A method of estimating the value of in situ surface tension on a bubble wall

The surface tension of a liquid is an important parameter for estimating and analyzing the processes that happen on the air/liquid interface, such as the air/sea gas exchange. Current methods of measuring surface tension concentrate on measuring its value at the top flat air/liquid interface. However, in cases where bubbles mediate oceanic processes (such as their contributions to air-to-sea transfers of mass, energy, and momentum), the value of surface tension that is needed (e.g., for placement in models of the evolution and persistence of sub-surface bubble clouds) is the instantaneous value on the bubble wall, as it moves through the ocean and potentially collects surface-active species onto the bubble wall. This paper outlines a method of estimating the value of this in situ surface tension, by insonifying a bubble and observing the onset of Faraday waves on a bubble wall. This new method was compared with a traditional ring method in various scenarios.