Ginis, I., and G. Sutyrin, 1995: Hurricane-generated depth averaged
currents and sea surface elevation. Journal of Physical Oceanography,
25(6) Part I, 1218-1242.
Abstract: A theory of the depth-averaged currents and sea surface
elevation generated by a moving hurricane in a stratified ocean with flat
bottom is presented. Using a scale analysis of the depth-integrated momentum
and continuity equations, it is found that the depth-averaged currents
are nearly nondivergent and determined entirely by the wind stress curl.
Earth's rotation and ocean stratification have negligible effects. The
sea surface elevation is decomposed into four physically different parts
caused by geostrophic adjustment to the depth-averaged currents, wind stress
divergence, inverted barometer effect, and baroclinic effects. When a hurricane
moves with a uniform speed, it generates quasi-stationary, alongtrack,
elongated depth-averaged currents. The sea surface elevation remaining
after the hurricane passage is a combination of a trough geostrophically
adjusted with the depth-averaged currents and a sea surface elevation associated
with baroclinic effects.
The barotropic response is analyzed for different wind stress distributions.
A universal nondimensional description of the depth-averaged flow is suggested,
using scaling based on the maximum wind stress torque LtL
and its radius L. This marks the primary difference with baroclinic
responses where the radius of maximum winds, Rm,
and maximum wind stress tm are the
determining scales. For all cases considered, the maximum depth-averaged
current is proportional to LtL and
the distance from the maximum to the storm track is proportional to L.
The wind stress behavior at the hurricane's periphery is shown to be an
important feature in determining the sea surface response.
Analytical solutions of approximated equations agree well with numerical
simulations based on the full set of equations. It is demonstrated, using
a two-layer model, that nonlinear coupling between the baroclinic and barotropic
modes is rather weak, and therefore they may be calculated separately.