Kl. Polzin et al., FINE-STRUCTURE AND MICROSTRUCTURE CHARACTERISTICS ACROSS THE NORTHWEST ATLANTIC SUBTROPICAL FRONT, J GEO RES-O, 101(C6), 1996, pp. 14111-14121
Vertical profiles of temperature, salinity, horizontal velocity, rate
of dissipation of turbulent kinetic energy, and thermal variance are u
sed to examine the parameterization of turbulent mixing associated wit
h internal waves in an upper,ocean front. Previous attempts to quantif
y the rate of turbulent dissipation [e.g., Gi egg, 1989; Polzin et al.
, 1995] are based upon dynamical models of wave-wave interactions usin
g the Garrett and Munk [1979] (GM) spectrum. Non-GM conditions (vertic
al and horizontal anisotropy, deviations iii-vertical wavenumber and f
requency spectral shapes, and the presence of a background flow) may a
ffect the character of wave interactions, altering the upwavenumber en
ergy flux, which is equated with the rate of turbulent dissipation; No
n-GM conditions in the data are documented, and revisions to the wave-
wave interaction models are discussed. Additionally, the strength of w
ave-wave interactions is directly compared with the strength of wave-m
ean flow interactions. These data indicate that the dissipation rate i
s relatively insensitive to the presence of a background flow and anis
otropic wave Conditions, in agreement with theoretical expectations ba
sed upon wave-wave interaction models and a model of wave-mean flow in
teraction at high background. Richardson number. These data support th
e findings of Polzin et al. [1995], who argue that the dissipation rat
e is most sensitive to variations in wave frequency.