1957～2004年中国不同强度级别降水的变化趋势特征

CHANGES IN CHINA'S PRECIPITATION IN VARIOUS CATEGORIES DURING 1957～2004

关键词:  中国降水  降水频率  降水强度  变化

Key words:  China’s precipitation  precipitation frequency  precipitation intensity  changes

摘要:

利用1957～2004年我国506个测站的逐日降水观测资料,分析我国8个区域年降水量、年降水频率和平均降水强度的趋势变化,根据百分位的分布,分析不同强度级别降水量和降水频率的趋势变化,以及频率和强度变化分别对降水量趋势的贡献。结果表明,年降水量、降水频率和平均降水强度均存在明显的区域变化特征。针对不同强度级别降水量和降水频率的趋势分析表明,极强降水量的趋势变化最为明显,频率变化在各强度级别均有体现,降水量的趋势变化主要由强降水量的变化引起,降水频率变化对降水量趋势的贡献远大于强度变化,趋势变化主要由频率的趋势产生。

Abstract:

On the basis of 506 stations with complete daily precipitation records during 1957～2004,the trends of China's annual precipitation totals,annual precipitation frequencies and mean precipitation intensities are studied. Annual precipitation amounts and precipitation frequencies are additionally studied with a focus on different percentiles. The contributions to trends in precipitation amounts attributing to changes in frequencies and intensities for various categories are further analyzed. Regional trends are found in annual precipitation totals,annual precipitation frequencies and mean precipitation intensities. Trends in heavy precipitation amounts are more significant and changes in heavy precipitation primarily cause the variations in precipitation totals. For most of the categories,the variations of precipitation due to the changing of precipitation frequencies are much greater than those resulted from precipitation intensities. That is to say,trends in precipitation are mainly caused by changes in precipitation frequencies.