This work considers observed changes in tropical Pacific Ocean rainfall amounts and the influence of climate variability cycles upon them. Observations were taken from the Comprehensive Pacific Rainfall Database (PACRAIN), using strict data selection criteria of >99% data completeness from eight locations for the period 1971–2017. These data were used to analyze temporal and spatial rainfall patterns based on several indicators that considered rainfall amount and frequency, 95th percentile extreme rainfall events, and length of consecutive rain/drought events. These indicators were also computed using satellite-derived observations from the Global Precipitation Climatology Project (GPCP), as a means to compare gauge-based values with nearby estimates from the GPCP product. Results show a temporal pattern that tended towards a reduction in rainfall amounts and frequency across the tropical Pacific Ocean. The impact of phase changes of the Interdecadal Pacific Oscillation (IPO) was also examined. There was some evidence of the impact of the IPO, as well as of the El-Niño Southern Oscillation (ENSO), when seasonal and monthly trends in these indicators were analyzed. Comparison of the temporal patterns observed from the rain gauges with the trends computed using the GPCP estimates showed inconsistencies that varied considerably when comparing trends calculated at different island locations. Future work should consider further comparison of GPCP and gauge-based rainfall trends, as well as the attribution of climate change and other climate variability cycles to these trends.

这项工作考虑了热带太平洋降水量的观测变化以及气候变化周期对其的影响。观测数据来自太平洋综合降雨数据库（PACRAIN），使用严格的数据选择标准，即在1971-2017年期间来自八个位置的数据完整性> 99％。这些数据基于几个指标来分析时间和空间降雨模式，这些指标考虑了降雨量和频率，第95个百分位的极端降雨事件以及连续的降雨/干旱事件的持续时间。这些指标也是使用全球降水气候学项目（GPCP）的卫星观测值计算得出的，作为将基于仪表的值与GPCP产品的附近估算值进行比较的一种手段。结果显示出一种时间模式，倾向于减少整个热带太平洋的降雨量和频率。还研究了年代际太平洋涛动（IPO）相位变化的影响。分析这些指标的季节性和月度趋势时，有一些证据表明了IPO以及El-Niño南方涛动（ENSO）的影响。从雨量计观察到的时间模式与使用GPCP估计值计算出的趋势进行比较后发现，当比较在不同岛屿位置上计算出的趋势时，不一致之处变化很大。未来的工作应考虑进一步比较GPCP和基于雨量计的降雨趋势，以及气候变化和其他气候变化周期对这些趋势的影响。