中国东南及周边海区季尺度降水昼夜变化的特征分析

Analysis of Characteristics of Seasonal-Scale Diurnal Precipitation Variation over Southeastern China and Its Adjacent Seas

摘要: 利用1998~2014年间热带测雨卫星(TRMM)上搭载的测雨雷达(PR) 3G68 16年的观测资料，分析了中国东南及周边海区季尺度降水昼夜变化的区域特征。本文主要关注降水量、降水频次和降水强度的昼夜差异以及降水日变化对季节总雨量的贡献率。结果表明，降水量的季节性差异显著，我国东南部陆面春季和夏季降水较多，海面上夏季和秋季降水较多。从雨量昼夜差异来看，中国东南部和南海四季都以昼雨为主。降水日变化对季节总雨量贡献率的空间分布表明，南海日变化的贡献率高于其他地区，全年在40%以上，冬春季高达60%~80%；中国东南沿海降水日变化对雨量的贡献在夏季最大；东海降水日变化对雨量贡献率的季节差异不明显。

Abstract: Using 16 years of observational data (1998~2014) from the Precipitation Radar (PR) product 3G68 aboard the Tropical Rainfall Measuring Mission (TRMM) satellite, this study analyzes the regional characteristics of seasonal-scale diurnal precipitation variations over Southeastern China and its adjacent seas. The paper focuses on the diurnal differences in precipitation amount, precipitation frequency, and precipitation intensity, as well as the contribution rate of diurnal variation to the total seasonal precipitation. The results show significant seasonal differences in precipitation amount. Land areas in Southeastern China receive more precipitation in spring and summer, while sea surfaces experience more precipitation in summer and autumn. In terms of diurnal differences in precipitation amount, daytime precipitation dominates over both Southeastern China and the South China Sea in all four seasons. The spatial distribution of the contribution rate of diurnal precipitation variation to total seasonal precipitation indicates that the contribution rate over the South China Sea is higher than in other regions, exceeding 40% throughout the year and reaching 60%~80% in winter and spring. Along the coast of Southeastern China, the contribution of diurnal precipitation variation to total precipitation is greatest in summer. The seasonal difference in the contribution rate of diurnal precipitation variation to precipitation amount over the East China Sea is not significant.