This web page presents the output from two 8 day free surface simulations forced with a combination of COAMPS (wind stress) and NOGAPS (heat-flux, E-P) atmospheric forcing, initialized using the Taiwanese in situ data and a summer climatology created using June-August profiles and the HydroBase2 software. The bathymetry used is the NCOR bathymetry.
In our simulations so far, an uncertainty source is still the transport just north of Taiwan. We have decided to change one of the 2 forecasts types we issued today: one still has an initial 1Sv northward transport but the other now has an initial 1Sv southward transport through the Strait (instead of the data-driven freely computed transport of 2.5Sv S). Of course, these boundary transports change with time, based on the interior flows and open boundary conditions. A second uncertainty source is the impact of tidal effects on the mesoscale hydrographic and circulation features in the forecasts, especially just north of Taiwan. We have several simulations which include tides which we are currently studying and comparing.
From the OR2 and OR3 data we have from last week, the SST data and our varied model simulations which assimilate the OR2-OR3, we still believe there is some upwelling of deeper Kuroshio water on the shelf just north of Taiwan, with nice filaments being advected north-eastward along the shelfbreak on the edge of the Kuroshio (this seems to match the older SST analyses from the Taiwan Central Weather Bureau). This would indicate that subtidal currents just north of Taiwan are westward. Associated with this is a relatively classic situation of a meander of the Kuroshio in the QPE area. In summary, this means that the forecast initialized with a "1Sv southward transport in the Taiwan Strait" should be closer to the truth. However, we are not yet certain; more study is needed, including the impact of tidal forcing.
Acoustic simulations from each of these two dynamical simulations, with vertical sections of transmission loss (TL) and sound speed, can be found here.
|Nowcasts and Forecasts of Environmental Conditions|
|Initial Transport||50m Temperature||50m Salinity||50m Velocity||Complete set of Plots|
|Nowcast - 7 September||Forecast - 8 September||Nowcast - 7 September||Forecast - 8 September||Nowcast - 7 September||Forecast - 8 September|
|1.0Sv S||X||1.0Sv N||X|
|Available NetCDF Files|
|1.0Sv S||Along Grid||peout_1SvS06sep2008.nc.gz|
|1.0Sv N||Along Grid||peout_1SvN06sep2008.nc.gz|