Comparison of Vertical Mixing Parameterizations for
the Wind-driven Coastal Ocean.
Scott Durski
College of Oceanic and Atmospheric Sciences
Oregon State University
The Mellor-Yamada level 2.5 closure scheme is compared to an enhanced
version the K-profile parameterization developed by Large, McWilliams
and Doney for application to wind-driven coastal ocean circulation.
Two features of the coastal ocean are examined in particular. 1) The
level of stratification in the coastal ocean can range from well mixed
to many times higher than that typically observed in the open ocean.
The performance of the two schemes (forced by a surface stress) over
this range of stratifications is compared and significant qualitative
differences between formulations are noted. 2) The shallowness of the
water column in the coastal ocean presents the potential for
surface-bottom boundary layer interaction. Within ROMS, the Large
et al. parameterization is appended to include a representation
of a neutral bottom boundary layer, modeled after their surface boundary
layer formulation. The two parameterizations are then compared over a
range of statification in one-dimensional and two-dimensional
experiments in which surface and bottom boundary stresses promote
vertical mixing. Again qualitative differences arise which can be
explained by how the two schemes represent mixing.