A summary of the broad scale tropical circulation from 70°E to 180°, for the six months November 2002 to April 2003, is presented. Transition from a moderate warm ENSO (El Niño) phase to near neutral conditions was evident during the season. Evidence for this includes transition to near average Walker circulation over the Australian region, slightly above average but weak atmospheric pressure over the central equatorial belt, negative values of the Southern Oscillation Index which were mostly confined to within one standard deviation of the mean and a zone of warm sea-surface temperature anomalies in the equatorial central Pacific. Overall convection over much of western Indonesia and northern Australia was below average, with the monsoon being poorly developed in the northern Australia and Papua New Guinea region for most of the season. Active phases of the Madden-Julian Oscillation (MJO) were clearly evident during the transition stages either side of the north Australian Monsoon, but more difficult to interpret during the middle part of the season. A total of 25 tropical cyclones developed during the period, close to the mean for the season.
Shalk et al. (Mon,) studied this question.