TURBULENCE AND MIXING IN STABLY STRATIFIED WATERS

Stable stratification seems to suppress the turbulence enough so that interesting events are somewhat spread out in space and time. Most particularly, there seem to be unique opportunities to identify and trace to its source the particular energy supply tapped by the small-scale motions that do the mixing in various circumstances. This provides the organizational theme for this review, and mixing motions in three categories are discussed: those deriving their kinetic energy from the gravitational potential energy of a water column that is in some sense top-heavy; those that covert to smaller scales the kinetic energy associated with large-scale shear flows or internal waves; those that are driven by some fairly obvious external source of small-scale agitation. Here we think particularly of the wind mixing of surface waters.