ESS228
Prof. Jin-Yi Yu
Equatorial b-Plane Approximation
•f-plane
approximation: On a rotating sphere
such as the earth, f varies with the
sine of latitude; in the so-called f-plane approximation, this variation is ignored, and a value of f appropriate for a particular
latitude is used throughout
the domain.
•β-plane approximation: f is set to vary linearly in space.
•The advantage of the beta plane approximation over more
accurate formulations is that it
does not contribute nonlinear terms to the dynamical equations; such terms make the equations harder to
solve.
•Equatorial
β-plane approximation:
• cosφ » 1,
sinφ » y/a.
and