Generation of Equatorial Kelvin, Yanai and Short n = 1 Rossby Waves Near a Western Boundary, and Long n = 1 Rossby Waves Near an Eastern Boundary

This poster is a numerical exploration of waves on an equatorial beta plane in a

rectangular basin whose boundaries intersect the equator at an arbitrary angle.

The waves are forced by a pressure source on the western boundary away from

the equator on the western side of the basin, either northeast or southwest of

the equator , started from rest and spun up numerically.

At the 2015 AOFD meeting we choose a forcing frequency for which the only

modes with real wave numbers were Equatorial Kelvin Waves and Equatorial

Mixed Rossby-Gravity (Yanai) Waves. The non-dimensional frequencies were

between 1 - sqrt (1/2) and 1 + sqrt(1/2) , or approximately 0.3 and 1.7 .

In this study we have lowered the forcing frequency slightly, so that short and long

Rossby waves with u and p symmetric about the equator and v anti-symmetric

are also possible . So we force at frequency equal to 0.25 to investigate this case.

The availability of the Rossby modes drastically changes the character of the

energy partition on the eastern boundary, as well as the length of time it takes

to reach a quasi-steady state.

All the unusual energy partition results when the the only propagating modes are Kelvin and Yanai

waves change drastically when short and long Rossby waves come into play.