  The Model Coupling Executable Library (MCEL), developed at the University of
Southern Mississippi's Center of Higher Learning, has been successfully used to
couple the Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS) and
the ocean wave model WAVEWATCH. An example of its application is shown for
Hurricane Gordon, showing that two-way coupling results affects boundary layer
physics differently than one-way coupling --- in this case, resulting in larger
z_o and, consequently, larger surface fluxes and a more intense hurricane.
However, since analyzing MCEL is difficult because the wave physics is
inaccurate, improvements to the wave algorithms are also part of the
deliverables. A new analytical expression for the wind/wave growth factor has
been derived based on normal modes analysis and rapid distortion theory valid
for all wave regimes except for tropical cyclone conditions. This new algorithm
is validated against a numerical simulation of the Reynolds-stress transport
equations and matches well. In contrast, other wave growth expression used in
ocean models like the WAve Model (WAM) and WAVEWATCH do not produce the same
results, with larger wave growth values peaking at smaller wave age values.
These differences are attributed to the application of curve fitting by the
other algorithms, while the new formulation is an analytical expression derived
from first principles and includes factors missing in previous schemes such as
turbulent interaction. If the Reynolds-stress transport equations solutions are
reasonably accurate, it indicates that all the previous wave growth schemes,
including WAVEWATCH, have serious deficiencies. Another unique result from this
work includes a second analytical wave growth formulation valid for tropical
cyclone conditions.

Atmospheric and Oceanic Physics