Eighteen tropical cyclones formed in the South Pacific and southeast Indian Ocean during the 2002-03 tropical cyclone season. This total was just below the overall average and followed on from below-average activity in previous seasons. There was a marked shift in cyclone activity away from the Australian region towards the South Pacific, consistent with the prevailing moderate warm ENSO (El Niño) event. Only two cyclones occurred between 125° and 150°E whereas ten occurred east of 160°E. Of these ten systems, seven produced hurricane-force winds (sustained winds of at least 33 m/s). Furthermore three of these, Zoe, Ami and Erica caused significant damage to the eastern Solomon Islands, New Caledonia and Fiji, and Tuvalu respectively. Zoe and Inigo (NWAustralia) both had estimated maximum sustained winds of 67 m/s, making them amongst the most intense systems ever experienced in the region. The 18 cyclones that formed spanned every month between December 2002 and June 2003 except for May. The five active phases of the intraseasonal (Madden-Julian) oscillation (MJO) coincided with the development of thirteen of the eighteen cyclone events. Equatorial Rossby (ER) waves assisted in the genesis of four of these systems and with the development of a further four outside an active MJO phase. Only one cyclone (Zoe) was completely removed from an identified MJO or ER wave episode.
J.B. Courtney (Wed,) studied this question.