-
M. Çalık and M. Oliver,
Weak solutions for generalized large-scale semigeostrophic equations,
Commun. Pure Appl. Ana. 12 (2013), 939-955.
Abstract:
We prove existence, uniqueness and continuous dependence on initial
data of global weak solutions to the generalized large-scale
semigeostrophic equations with periodic boundary conditions. This
family of Hamiltonian balance models for rapidly rotating shallow
water includes the L1 model derived by R. Salmon in
1985 and its 2006 generalization by the second author. The analysis is
based on the vorticity formulation of the models supplemented by a
nonlinear velocity-vorticity relation. The results are fundamentally
due to the conservation of potential vorticity. While classical
solutions are known to exist provided the initial potential vorticity
is positive---a condition which is already implicit in the formal
derivation of balance models, we can assert the existence of weak
solutions only under the slightly stronger assumption that the
potential vorticity is bounded below by √5-2 times the
equilibrium potential vorticity. The reason is that the
nonlinearities in the potential vorticity inversion are felt more
strongly when working in weaker function spaces. Another
manifestation of this effect is that point-vortex solutions are not
supported by the model even in the special case when the potential
vorticity inversion gains three derivatives in spaces of classical
functions.
Download the paper in
PDF
format.