Madden-Julian Oscillation (MJO)
Meat & Livestock Australia October 20, 2023
The Madden-Julian Oscillation (MJO) is a tropical weather pattern that is very important for northern Australia, but can also influence rainfall and temperature patterns across southern Australia. Depending on the phase and time of year, the MJO can influence the likelihood of wetter or drier conditions, although it has a greater impact on Australia in the northern wet season.
The MJO is characterised by a band of clouds, rainfall and winds moving eastward across the tropical Indian Ocean into the western Pacific Ocean, every 30-60 days.
When the MJO is in its enhanced phase to the north of Australia, this can increase the chance of rainfall across Australia’s northern regions. However, when the MJO is in its suppressed phase, this can lead to drier conditions and even failed northern wet seasons.
The following videos explain the impact of MJO and how it behaves.
Key points
- For much of northern Australia, MJO phases 8 & 1 are ‘dry’ and 5, 6, & 7 are ‘wet’.
- A ‘wet’ MJO phase in December can bring the first monsoon rains.
- The MJO can also be weak or inactive when passing over Australia and, when this happens, it does not have any impacts or influence on our weather.
- Strong MJO activity can lead to tropical cyclone development.
- MJO can be important for: Burning, spraying, planting, harvesting, mustering.