Looking into the water

Abstract

The observation that the small bubbles, 40-300 nm across, in the white cap of a breaking wave remain in the water just below the surface after the wave has passed has led to the development of a technique for measuring the subsurface current that does not entail the equipment being battered by waves: in fact it can sit snugly on the bottom. The sonar observation of these small bubbles as they are carried along by the current, as well as of the breaking waves themselves, is described in a letter to Nature (1982 296 636) by S A Thorpe and colleagues at the Institute of Oceanographic Sciences, Godalming, and R J Turner of Surrey University.