Numerical Simulations of the CCS under the Joint Effects of Coastal Geometry and Surface Forcing

Song, Yuhe; Haidvogel, Dale; ,

Numerical Simulations of the CCS under the Joint Effects of Coastal Geometry and Surface Forcing

by Yuhe Song, Rutgers Univ, New Brunswick, United States,
Dale Haidvogel, Rutgers Univ, New Brunswick, United States,

Document Type: Proceeding Paper

Part of: Estuarine and Coastal Modeling

Abstract:

Using the S-Coordinate Rutgers University Model (SCRUM) of Song and Haidvogel(1993), a coupled coastal (86 m depth) and deep ocean (4600 m depth) California Coastal region has been investigated for the dynamics of the California Current System (CCS) under the joint effects of realistic coastline geometry, bottom topography, wind forcing, and surface heat flux. The model equations are the three-dimensional, free surface, primitive equations with orthogonal curvilinear coordinates in the horizontal and the s-coordinate in the vertical. Three kinds of surface forces - steady wind field with positive curl, long-term oscillatory wind, and diurnal cycling wind and thermal forcing - are used to simulate the variations of the CCS. Two alternate parameterizations, dynamic instability mixing and turbulence closure mixing, are used in the diurnal cycling problem. The model is shown to be stable and capable of handling the joint effects of geometry and surface forcing. Our simulations show that: (1) upwelling and a depressed surface height are always found at the coast for equatorward wind stress; (2) the equatorward surface jet and the poleward undercurrent persist for all upwelling-favorable winds; (3) a meandering jet and eddies can be caused by the coastline geometry and wind curl in combination; (4) surface and bottom layers mixing increases the variations of the CCS.

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