HR: 14:55h
AN: OS32C-06    [PDF]
TI: The Effect of Lateral Intrusions on Thermohaline Fronts - Diffusive or Frontogenetic?
AU: * Simeonov, J A
EM: simeonov@ocean.fsu.edu
AF: Department of Oceanography Florida State University, Oceanography/Stat. Bldg., West Call, Tallahassee, FL 32306
AU: Stern, M E
EM: stern@ocean.fsu.edu
AF: Department of Oceanography Florida State University, Oceanography/Stat. Bldg., West Call, Tallahassee, FL 32306
AB: A density compensated thermohaline front with a finite width and specified total lateral salinity variation, superimposed on a finger favorable thermocline is studied by means of linear theory and non-linear numerical calculations using parameterized finger fluxes. By retaining the relatively small molecular heat diffusion and the dependence of the finger Nusselt number Nu on the density ratio, we show that marginal stability with critical frontal salinity variation is possible. The lateral eddy fluxes induce a mean vertical velocity which can sharpen the front, but when the frontal salinity variation exceeds a certain supercritical value the effect of the eddy fluxes exceeds that of the mean vertical velocity and the front diffuses. Non-linear 2D spectral calculations showed that the modification of the mean horizontal gradients is small and that the intrusions continue to grow exponentially even after they have produced overturns. By extrapolating our linear theory results beyond the overturning stage, the intrusion velocity was estimated to be proportional to the Brunt-Vaisala frequency multiplied by the intrusion thickness.
DE: 4203 Analytical modeling
DE: 4524 Fine structure and microstructure
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting