Marine Ecosystem Dynamics Modeling Laboratory

SAB FVCOM

Our previous modeling efforts in the SAB were relied heavily on the ECOM-si (a modified version of POM).  ECOM-si is a structured grid finite-different model coded with the semi-implicit scheme. This model is suitable for the process-oriented study, but it fails to resolve estuarine-shelf interaction process because of its poor fitting in the complex irregular geometry of the coastline, islands, barriers, and tidal creeks.  This is the reason that we started using FVCOM in 2001. 

The SAB FVCOM is configured with unstructured triangular meshes covering the entire SAB shelf (Fig. 1). The horizontal resolution varies from 500 m in the inner shelf and around islands to 15 km near the open boundary.  31 non-uniform sigma-levels are used in the vertical, which corresponds to a vertical resolution of less than 1 m near the coast and 10 m near the surface and bottom off the shelf.  Forcing includes 5 tidal constituents at the open boundary, freshwater discharges from rivers, and assimilated MM5-predicted wind stress and heat flux. 

Tidal experiment was carried out by Jinnan Chen, a visiting scholar from China in 2002. By comparing with the tidal elevation data recorded at coastal tidal gages and tidal ellipses at the moorings, FVCOM accurately simulate both tidal elevations and currents in the SAB. By better fitting the coastal geometry, FVCOM significantly improved the accuracy of tidal simulation in this region.

We also examined the impact of various turbulent closure models on tidal elevation and currents. No significant differences were found from experiments with MY 2.5 and k-e 2-equations turbulent models except near the bottom.

Current SAB FVCOM has been merged to the global Atlantic FVCOM as a sub-grid domain along the US southeastern shelf. This model can be either run together with the global ocean scale FVCOM or operated separately through one-way nested approach.

For more information about the updated results of the SAB FVCOM, please contact Dr. Changsheng Chen directly at c1chen@umassd.edu

Unstrucuterd meshes. The horizontal resolution is 500 m along the coast and around islands and varies from 10 to 15 km near the open boundary. This is our preliminary grid. The new mesh has increased the horizontal reoslution to about 20 m around the coast and also linkes to estuaries. The new grid was generated as a subgrid for the global Atlantic Ocean FVCOM.

We have collected all available measurement data of tidal elevation at tidal gages and tidal currents at moorings for validating FVCOM.

 

3-D tidal animation of the surface elevation and near-surface tidal current vectors. This animation was made by well-calibrated tidal model output. Only tidal forcing was included in this experiment. The animation was made with selected grid point to make the vector field view clearly.

We also compared the model-predicted tidal current ellipses with the field measurement data. The results show that FVCOM accurately re-produce the realistic tidal current distribution in the SAB and also vertical shear of the current profiles. For detailed comparison results, please contact Dr. Changsheng Chen directly.Click figure to view the animation

«PreviousNext» Posted on January 6, 2014