Research Projects

The Madden-Julian oscillation (MJO) is a slow eastward propagating system of tropical disturbances that is the dominant source of predictability in the sub-seasonal to seasonal timescale. Its persistent diabatic heating and large scale circulation can be stationary compared to synoptic scale disturbances. However, a mechanistic framework for the scale interaction between the MJO and synoptic scale variability and its impact on tropical weather is still missing. The MJO exerts significant control on tropical weather by impacting the genesis, strength, and characteristics of equatorial wave modes. The major modes of tropical synoptic scale disturbances are the westward propagating Mixed Rossby-Gravity (MRG) waves and eastward propagating Kelvin waves. The MJO's asymmetric diabatic heating in the tropics may control the frequency of these wave events. The lowering of gross moist stability of the atmosphere by MJO may also contribute to an increase in convection-circulation coupling strength, enhancing the vertical propagability of the waves. Quantifying the relative contribution of MJO in modulating tropical disturbances could provide an estimate of the predictability of these systems.