Feature article
Pacific Island weather and the MJO
Dr Mike Revell, NIWA
The Madden-Julian Oscillation (MJO) is the major mode of variability of the tropical atmosphere-ocean system on time scales of 30 to 70 days. The MJO organizes convection into an eastward-propagating envelope of smaller-scale disturbances. This envelope moves eastward at between 5 and 10 ms-1 on average, generally forming in the tropical Indian Ocean and dissipating over the central Pacific. It is generally most active during the southern hemisphere summer and autumn.