MJO Monitoring & Forecast

Real-time RMM1 and RMM2 indices are sourced directly from the Australian Bureau of Meteorology (BOM), computed using the Wheeler-Hendon (2004) method.

Forecast RMM indices are computed from ECMWF IFS open data using three atmospheric fields: 850 hPa zonal wind (U850), 200 hPa zonal wind (U200), and outgoing longwave radiation. ERA5 climatology is used to compute daily anomalies for each field. The anomalies are normalised using standard deviation scalars derived from ERA5 filtered anomaly data, then projected onto the Wheeler-Hendon EOF patterns to produce RMM1 and RMM2 Phase and amplitude are then computed from the resulting indices.