The impact of the MJO - Bridging the gap between weather and climate

Abstract

The Madden-Julian Oscillation (MJO) is a tropical atmospheric phenomenon, associated with periods of active convection in the eastern hemisphere tropics. The MJO's temporal scale (events happen at intervals from 22-90 days) coincides with a gap between weather and climate forecasts. Application of MJO data begins to address this gap. The RMM Index is an MJO proxy and indicates the amplitude and location (Phases 1-8) of MJO active convection. Analysis demonstrates that the MJO influences weather well beyond the tropics, on this intraseasonal timescale. We analysed global rainfall data (summer/winter rainfall patterns) with respect to the RMM Index phases of the MJO. Observed MSLP frequencies are at least partially explained by the MJO and advance a causal relationship between the tropical MJO and tropical and extra-tropical rainfall and MSLP anomalies.