Anisotropy of Salt Fingers

Abstract

Abstract An understanding of the structure of the vertical temperature and salinity profiles in salt fingers is required to identify the occurrence of fingers in vertical profiles of oceanic microstructure and hence to make estimates of the contribution of fingers to vertical mixing in the ocean. With this in mind, a laboratory experiment was set up in which the vertical temperature and conductivity profiles through salt fingers were measured and compared with horizontal profiles of the same quantities. It was found that the vertical component of the temperature gradient in salt fingers had few zero crossings, so was quite different from the temperature gradient that would result from turbulence. On the other hand, the conductivity gradient (which is dominated by changes in salt concentration in our experiments) had numerous zero crossings even when the salt fingers were relatively weak. For density ratios Rp < 5 (where Rp = αθ¯z/βSz and θ¯z and Sz are the mean vertical gradients of potential temperatur...