Abstract:

Hourly precipitation data of 1457 stations during 1980?2012 were used to investigate the spatial-temporal patterns of PCI (precipitation concentration index) from May to September over eastern and central China. The relationships between PCI and other precipitation variables based on different precipitation intensities or different precipitation durations were also analyzed to reveal the variables highly correlated with PCI. The result indicated that the values of PCI over eastern and central China ranged from 0.56 to 0.78 with evident regional variations. The values of PCI in southeastern China were higher than the values in northwestern China. There were three concentrations of high PCI value centers, i.e., Northeast China, North China, and Sichuan Basin. The variations of PCI were found in areas with great altitude difference. The linear trend analysis showed an increasing trend of PCI values over eastern and central China over the past 33 years. In addition, significantly positive correlation relationship between PCI and extreme precipitation was detected, and the correlation coefficient of the two variables increased with the decrease of the total precipitation amount.

Key words: hourly precipitation, PCI (precipitation concentration index), spatial-temporal patterns, extreme precipitation

摘要：

基于 1980—2012 年 1457 个站点小时降雨数据, 研究我国中东部地区 5—9 月降雨集聚指数(PCI)的时空分布特征, 探索 PCI 与不同降雨强度和不同持续时间小时降雨变量之间的关系, 揭示影响PCI变化的降雨特征变量。研究结果表明: 我国中东部地区 PCI 在 0.56~0.78 之间, 并具有明显的区域差异。东南沿海 PCI高于西北内陆, 在东北、华北及四川盆地形成 3 个高值中心, 并在海拔差异较大的地区发生突变。线性趋势分析表明, 我国中东部地区近 33 年 PCI 呈上升趋势。PCI 与极端降雨之间呈显著正相关, 且随着降雨量的减少, 相关性显著增强。

关键词: 小时降雨, 降雨集聚指数(PCI), 时空特征, 极端降雨