Reynolds stress observations in continental shelf seas

The three basic observational approaches to estimating turbulence parameters in continental shelf seas are free-fall micro-structure probes from which dissipation is inferred; fast-sample (10–20Hz) current meters in sea-bed frames measuring turbulence intensity directly; and fast-sample O(1Hz) high-frequency Acoustic Doppler Current Profilers (ADCPs) where Reynolds stress profiles and hence turbulence production can be estimated from the variance of the along beam data. Uncertainties are associated with each approach since turbulence is a small-scale, high-frequency phenomenon and since estimates can easily be contaminated by the presence of surface waves. This paper concentrates on the latter two approaches, particularly the ADCP method, focussing on the degree of confidence that can be placed on the estimates.