HR: 16:15h
AN: OS14A-02    [Abstracts]
TI: Statistical representation of heterogeneous oceanic convection
AU: Tziperman, E
EM: eli@eps.harvard.edu
AF: EPS - Harvard University, 20 Oxford St, Cambridge, MA 02138 United States
AU: * Pasquero, C
EM: claudia@gps.caltech.edu
AF: GPS - California Institute of Technology, MC 100-23, Pasadena, ca 91125 United States
AB: Observations in regions of oceanic convection, such as the Labrador Sea, show that salinity and temperature fields have small- and meso-scale variability. Mesoscale eddies are believed to play an important role in reducing vertical stability in the preconditioned region. Convective mixing results from the formation of small scale vertical plumes and from nearly isopycnal motion driven by the convectively induced baroclinic instability of mesoscale eddies. The complexity of the convective mixing is usually replaced by a convective adjustment scheme in large scale models that cannot reproduce the dynamics of convection. We here propose a convective scheme that accounts for the subgrid scale variability of temperature and salinity. This allows us to calculate the probability that there are sub-grid locations that are statically unstable, and to derive the effects of the sub-grid scale convection on the grid-averaged water properties. Convective mixing in heterogenoeus conditions creates temperature-salinity correlations that are captured by this approach. Impact on heat fluxes is also discussed. The scheme may prevent spatially and temporally intermittent behaviour of convection normally seen in general circulation models, that does not seem to have an analogous in the reality.
DE: 4255 Numerical modeling (0545, 0560)
DE: 4271 Physical and chemical properties of seawater
DE: 4490 Turbulence (3379, 4568, 7863)
DE: 4515 Deep recirculations
DE: 4964 Upwelling (4279)
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005