HR: 13:50h
AN: OS43B-02    [Abstracts]
TI: A Numerical Study on Kuroshio Frontal Eddies at the Shelf Edge of the East China Sea Using a Finite Volume Coastal Ocean Model
AU: * Isobe, A
EM: aisobe@whoi.edu
AF: Physical Oceanography Dept., Woods Hole Oceanographic Institution, Clark,MS21, Woods Hole, MA 02543 United States
AU: Beardsley, R C
EM: rbeardsley@whoi.edu
AF: Physical Oceanography Dept., Woods Hole Oceanographic Institution, Clark,MS21, Woods Hole, MA 02543 United States
AB: Cross-frontal transports of seawater and materials are induced by nonlinear frontal eddies as they grow from baroclinically unstable frontal waves. It is difficult to measure these transports based on field observations and/or analyses of archived datasets because of intense spatiotemporal variability of frontal waves. In order to evaluate cross-frontal transports induced by frontal eddies quantitatively, it is therefore reasonable to use a numerical model approach that includes realistic bathymetric irregularities that may trigger frontal waves and eddies. The Finite Volume Coastal Ocean Model (FVCOM; Chen et al., 2003) is useful because this model features an unstructured grid that can resolve complex bottom topography. In this study, FVCOM is used with the Princeton Ocean Model (POM) to study Kuroshio frontal eddies in the East China Sea. First, the large-scale circulation in the Yellow and East China Seas is simulated using POM with inflow-outflow conditions of ocean currents (i.e., Kuroshio, Taiwan and Tsushima Currents), heat and freshwater fluxes through the sea surface, and the Changjiang river run-off. These conditions vary in time with an annual period. The model reaches a stable state with an annual cycle after seven years of spinup. The seventh-year POM results are then used as boundary conditions to drive FVCOM in a limitted area along the shelf break where the Kuroshio frontal eddies are frequently detected by field measurements and satellite infrared images. FVCOM reproduces frontal eddies with a folded-wave pattern, which is a characteristic of a mature frontal eddy. In addition, modeled eddies have wavelengths of 100-200 km and periods of 10-20 days, which are consistent with those observed in this area. Model results are compared with the temperature time series observed at a Japan Meteorological Agency buoy located at East China Sea shelf break, and are used for the quantitative evaluation of the cross-frontal transport in conjunction with passive tracer experiments.
DE: 4219 Continental shelf processes
DE: 4243 Marginal and semienclosed seas
DE: 4255 Numerical modeling
DE: 4520 Eddies and mesoscale processes
DE: 4528 Fronts and jets
SC: Ocean Sciences [OS]
MN: 2005 Joint Assembly