1800年以来海河流域夏季降水量的定量重建及分析

根据现代降水量实测资料和历史旱涝等级资料,通过相关统计分析方法重建了海河流域1800—2012年间的夏季(6—9月)降水量序列.介绍了定量重建历史降水量的方法及其可行性、合理性,并对重建的时间序列进行了分析.研究表明:1800—2012年海河流域平均夏季降水量始终处于波动变化之中,且经历了13次降水量的转变;20世纪夏季降水量总体上较19世纪呈现出减少趋势,近100年和近60年期间夏季降水量的减少趋势更加明显;19世纪80年代至19世纪90年代是1800年以来最湿润的阶段,而20世纪90年代至21世纪10年代是整个时期夏季降水量的最低值;近200多年,海河流域夏季降水量变化存在2~8、10~15、22、25~30、35和55 a左右的准周期,但20世纪长周期波动具有逐渐变短的趋势.

Precipitation reconstruction and analysis in Haihe River basin since 1800

The summer rainfall series (June to September) in the Haihe River basin from 1800 A.D.to 2012 A.D.are reconstructed by statistic method,using data of the observed precipitation and the dryness and wetness grades in modern times.The quantified reconstruction of historical precipitation,with its feasibility and reliability areintroduced,and the time series of the reconstructed data are analyzed in this paper.The results show that the summer rainfall is always fluctuating and there are 13 shift terms in the basin during 1800-2012.Summer rainfall is generally less in the 20th century compared with that inthe 19th century,and the decreasing trend is most obvious in the last 100 years and the last 60 years.The 1880s-1890s is the moistest period,while the 1990s-2010s is the driest period.Power spectrum and wavelet analysis also show that the summer rainfall during 1800-2012 is characterized by inter-annual and inter-decadal oscillations with 2-8 a,10-15 a,22 a,25-30 a,quasi-35 a,and quasi-55 a period,and the long period oscillations are shortened in the 20 century.