Forecasting with the Madden-Julian Oscillation and the applications for risk management

The Madden-Julian Oscillation (MJO) is a tropical atmospheric phenomenon first recognised in the early 1970s. The MJO, also commonly known as the 40-day wave, develops over the Indian Ocean and then travels east across the tropics at 5-10 m/s. With a timescale ranging from 30 to 60 days, the MJO has a frequency of 6-12 events per year. In its active stage, the MJO is associated with increased convective activity. Trailing the active centre is region of suppressed convective activity and mean surface level westerly winds. Statistical analysis shows that the MJO can influence rainfall in Australia and elsewhere in the world, beyond the tropics. As MJO forecasting tends to bridge the gap between synoptic and seasonal forecasting, the potential for on-farm risk management is significant. Media summary The Madden-Julian Oscillation can be used for medium-term forecasts of rainfall. These forecasts may improve tactical risk management in agriculture. Key word