Open AccessTurbulence in an estuarine embayment: Observations from Beatrix Bay, New Zealand
Author(s) -
Stevens Craig L.
Publication year - 2003
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2001jc001221
Subject(s) - pycnocline , stratification (seeds) , turbulence , buoyancy , richardson number , oceanography , estuary , geology , benthic zone , water column , bay , environmental science , convective mixing , convection , boundary layer , forcing (mathematics) , atmospheric sciences , physics , meteorology , mechanics , seed dormancy , botany , germination , dormancy , biology
This study characterizes turbulence in a stratified estuarine embayment using measurements of temperature gradient microstructure. The water column was generally strongly stratified with only moderate tidal forcing. Dissipation levels and turbulence length scales in the surface mixing layer, the pycnocline, the fluid interior, and the benthic boundary layer were measured and compared with expectations based on previous work in different systems. Parameters important for modeling, including the measured dissipation ratio (Γ d ) and the gradient Richardson number ( Ri g ), were calculated. The observations highlight a number of points. (1) The lack of strong tidal flows means that buoyancy effects in estuarine embayments are more important than in the estuary‐proper. (2) The combination of reduced tidal mixing and interacting thermohaline stratification suggests the importance, in certain situations, of diffusive convection. (3) Despite the shallow depths (<40 m), a number of hydrodynamic regimes, vertically adjacent to one another, exist, resulting in a highly variable distribution of turbulence properties.