Numerical Modeling of Nearshore Circulation Using a
Primitive Equation Model
Priscilla Newberger and John S. Allen
College of Oceanic and Atmospheric Sciences
Oregon State University
As part of the NOPP funded project, Development and Verification of a
Comprehensive Community Model for Physical Processes in the Nearshore
Ocean, we are adapting the Princeton Ocean Model (POM) for use in the
nearshore region to describe the shortwave-averaged circulation. The
POM is a fully three dimensional primitive equation ocean model which
has been widely applied to coastal and large scale ocean modeling. Major
issues in the nearshore region include the parameterization of the
turbulent mixing under breaking waves including the determination of
appropriate boundary conditions for the turbulent quantities, appropriate
forms of the forcing by breaking waves for the depth dependent model and
the addition of a sub-model for the enhancement of bottom stress in the
presence of waves. We present the results of initial work in all these
areas. Both Mellor-Yamada and k-epsilon turbulence closure models
have been tested in a two dimensional context (variation with depth and
across shore). Each closure model has been implemented with and without
boundary conditions reflecting the increases in turbulence caused by
breaking waves. An efficient bottom boundary layer sub-model
parameterizing the influence of the waves on the bottom stress has also
been embedded in POM. The circulation model is forced by gradients
in radiation stresses from the incident breaking waves. The forcing
functions are obtained either directly from measured wave data or from
a wave transformation model initialized by offshore wave data. Additional
effects of rollers are included in some of the formulations.