Hendon, H. H., and M. L. Salby, 1996: Planetary-scale circulations forced by intraseasonal variations of observed convection. J. Atmos. Sci., 53, 1751-1758.


Interhemispheric differences of the Madden-Julian oscillation (MJO) are investigated in a linearized primitive equation model. Heating is prescribed from the observed life cycle of the MJO, in which anomalous convection is concentrated in the Eastern Hemisphere. The dynamical response in the Eastern Hemisphere has the form of a forced disturbance that involves Kelvin and Rossby components. These dynamical components propagate eastward along with the prescribed heating and have zonal wavenumber-2 structure, in accord with observed behavior. The behavior in the Eastern Hemisphere also resembles that emerging from frictional wave-CISK, in which heating follows autonomously from the circulation. When the prescribed heating collapses near the date line, the Rossby component dissipates. The Kelvin component, however, continues to advance across the Western Hemisphere, where it propagates at more than twice the speed of the disturbance in the Eastern Hemisphere. The disturbance in the Western Hemisphere, which likewise is in accord with the observed behavior, can be understood as the radiating response to transient heating confined to the Eastern Hemisphere.