An MJO Tracking Method

This presentation introduces a method of tracking eastward propagation of precipitation anomalies associated with the MJO. This MJO tracking method provides quantitative and objective information of the strength, propagation speed, and timing of MJO precipitation over a given longitudinal region, such as the Indian Ocean. It can be applied to individual MJO events in observations and model forecast or simulations, and thereby measures model skill of forecasting or simulating individual MJO events, especially the behaviors of their precipitation. It can also be applied to numerous MJO events to derive statistics of the three MJO quantities. Both utilities of MJO tracking are demonstrated in this presentation. An example of an MJO event in November 2011 illustrates that the error growth in MJO forecast is quite different for its strength, propagation speed, and timing.