Madden-Julian Oscillation

This page allows you to explore the relationship between the MJO phases and and its effect on rainfall and mean sea level pressure.

Phase: Season: Location:

Location of MJO

Rainfall Effect
Regions of enhanced rainfall conditions (blue) and suppressed rainfall conditions (red) are marked on maps for each phase.

MSLP Anomalies
Regions of anomalous high and low mean sea level pressure for each phase. Note that highs (red) are associated with dry conditions, and lows (blue) with rainy conditions. The anomalies indicate the regions of enhanced and suppressed rainfall we observe for Australia results from large scale influences of the MJO on the atmosphere.

Enhanced and Suppressed Rainfall

The rainfall maps show patterns of enhanced (blue) and suppressed (red) rainfall. This refers to statistical tests of rainfall distribution based on the 8 phases of the MJO. If the rainfall distribution is shifted toward more rain during an MJO phase, then the station is coloured blue. Conversely, if the rainfall distribution is shifted toward less rain (zero), then the station is coloured red. If there is no significant shift in the distribution, then the stations are left blank. For example, there is a shift in the rainfal distribution towatd more rain for many stations in eastern NSW during Austral summer Phase 5, during Austral Phase 2 many of the same stations exhibit a shift towards less rain than the normal (all MJO phases)rainfall distribution for that area, and during Austral phase 8, the rainfall distribution is much the same independant of the phase of the MJO.

While the size of the difference of the rainfall distribution is relflected by the depth of colour, rainfall distributions are different at each station, and so at this stage the size of the distribution is not potrayed as an amount (mm) of rainfall difference. For example (in Australia), a big shift in the distibution of rainfall in an arid area may result from ifferent rainfall amounts to a shift in rainfall distribution attributed to the MJO in a coastal region.