The sensitivity of propagation of the MJO-like anomaly observed in SPCAM to variations in the Aquaplanet Climate

The Moist Static Energy (MSE) budget for the MJO-like spectral feature observed in Super-Parameterized CAM running on a zonally symmetric aquaplanet is examined for several different SST configurations. The propagation speed of this feature is shown to increase as the width of the SST decreases. The budget analysis allows the diagnosis of the contributions of the various MSE sources and sinks to the changes in propagation speed. It is determined that the variation in propagation speed is primarily due to the differences in meridional advection of the mean MSE profile by the MJO winds. The narrower SST cases, having stronger MSE gradients, experience a greater MSE source due to this term, which is phased relative to the convection to increase the propagation speed. The meridional eddy advection, previously shown to be a dominant contribution to the MSE budget for propagation is seen to be quite constant between the various cases.