Extreme rainfall events in the South Pacific are widespread and affected by various factors on different time scales. We use daily rainfall data from 20 stations over the South Pacific to investigate the characteristics of extreme rainfall events from 1979 to 2018. For regional analysis, we group the stations into three clusters characterizing the western, the central, and the far eastern regions of the South Pacific Convergence Zone (SPCZ). Extreme rainfall events contribute to roughly 20% of the seasonal mean rainfall in all three clusters. Among all four factors considered, tropical cyclones (TCs) cause the highest increase in the probability (Δp_westernSPCZ~286%, Δp_centralSPCZ~84%, Δp_{fareasternSPCZ}~189%) of extreme rainfall events. The Madden-Julian Oscillation (MJO) is the second most important factor affecting the probability of extreme rainfall events, increasing it by 30–60% when the MJO is active over the western SPCZ in phases 5–6, over the central SPCZ in phases 6–7, and over the far eastern SPCZ in phases 8–1. The probability is reduced by the same order of magnitudes during the opposite dry phases of the MJO, i.e., phases 1–3 for the western and central SPCZ, and 3–6 for far the eastern SPCZ region. The probability of extreme rainfall events increases during La-Niña (El-Niño) conditions to the southwest (southeast) of the mean SPCZ by 27% (31%); however, the impact of the El-Niño and Southern Oscillation (ENSO) along the SPCZ is not apparent. Dynamical analysis shows that the favorable conditions for generating extreme rainfall events are associated with northwesterly moisture transport and its convergence. The impact of TCs, MJO, and ENSO on rainfall extreme events can be partly understood considering this dynamical analysis. Extratropical Rossby waves can trigger tropical disturbances, but their impact on extreme rainfall events is generally less important than of the TCs, MJO, and ENSO.

南太平洋的极端降雨事件十分普遍，并受不同时间尺度上各种因素的影响。我们使用来自南太平洋20个站点的每日降雨数据来调查1979年至2018年的极端降雨事件的特征。为了进行区域分析，我们将站点划分为三个集群，分别代表了西太平洋，中部和远东地区。南太平洋融合区（SPCZ）。在这三个集群中，极端降雨事件约占季节性平均降雨量的20％。在考虑的所有四个因素中，热带气旋（TCs）导致概率增加最高（_{ΔpWesternSPCZ〜286}％，_{ΔpcentralSPCZ〜84}％，_{ΔpfareasternSPCZ}〜189％）的极端降雨事件。Madden-Julian涛动（MJO）是影响极端降雨事件概率的第二个最重要的因素，当MJO活跃于西部SPCZ的第5-6阶段，超过中央SPCZ的阶段时，增加30-60％ 6-7，以及远东SPCZ的8-1阶段。在MJO的相反干燥阶段，即西部和中部SPCZ的阶段1-3，而远东SPCZ地区的3-6，则概率降低了相同数量级。在拉尼娜（El-Niño）条件下，平均SPCZ西南（东南）极端降雨事件的概率增加了27％（31％）；但是，沿SPCZ的厄尔尼诺和南方涛动（ENSO）的影响尚不明显。动力学分析表明，产生极端降雨事件的有利条件与西北水汽输送及其收敛有关。考虑到这种动力学分析，可以部分了解TC，MJO和ENSO对降雨极端事件的影响。温带的罗斯比波可以触发热带干扰，但是它们对极端降雨事件的影响通常不如TC，MJO和ENSO重要。