## Propagation of meridional circulation anomalies along western and eastern boundaries

D. P. Marshall and H. L. Johnson, *Journal of
Physical Oceanography*, **43**, 2699-2717.

**Abstract**

Motivated by the adjustment of the meridional overturning
circulation to localized forcing, solutions are presented from a
reduced-gravity model for the propagation of waves along western and
eastern boundaries. For wave periods exceeding a few months, Kelvin
waves play no role. Instead, propagation occurs through short and long
Rossby waves at the western and eastern boundaries respectively: these
Rossby waves propagate zonally, as predicted by classical theory, and
cyclonically along the basin boundaries in order to satisfy the
no-normal flow boundary condition. The along-boundary propagation
speed is c*Ld/delta where c is the internal gravity/Kelvin wave speed, Ld
is the Rossby deformation radius and delta is the appropriate frictional
boundary layer width. This result holds across a wide range of
parameter regimes, with either linear friction or lateral viscosity
and a no-slip boundary condition. For parameters typical of
contemporary ocean climate models, the propagation speed is
coincidentally close to the Kelvin wave speed. In the limit of weak
dissipation, the western boundary wave dissipates virtually all of its
energy as it propagates towards the equator, independent of
dissipation coefficient. In contrast, virtually no energy is
dissipated in the eastern boundary wave. The importance of background
mean flows is also discussed.

This manuscript is available as
a PDF file.