Observations of salt fingers in the central waters of the eastern North Pacific

Abstract

This paper presents direct measurements of the temperature signature of salt fingers, observed by a horizontally towed temperature sensor at a station in the middle of the subtropical gyre in the eastern North Pacific. The observed spectral shape compares favourably with predictions from the spectral model of Schmitt (1979a), in which a wide range of finger wave numbers grow. The buoyancy flux due to temperature across the fingering interface is estimated by three methods: a ‘direct’ determination from the observed temperature gradient variance and predictions from two laboratory flux laws. The order‐of‐magnitude agreement among these estimates is an encouraging start to the problem of parameterizing the heat, salt, and buoyancy fluxes associated with salt fingering in the Central Waters of the subtropical gyres, a very real problem in view of the widespread occurrence of salt‐fingering signatures in the towed temperature records.