华北地区降水多时间尺度演变特征

 华北地区的水资源短缺及相关的生态环境恶化是中国亟待解决的问题之一。降水是水资源最重要的因素，根据华北地区25个测站的长期年降水量资料和15个测站历史旱涝资料，利用Mann-Kendall检验、功率谱和小波变换等方法进行的分析研究表明，华北地区的降水存在明显的准2 a振荡和准19 a周期变化特征，降水在1914和1964年发生了两次突变。历史旱涝等级时间序列有明显的4～5 a ENSO模的振荡、准10 a变化、准20 a变化和50～80 a世纪尺度特征。

Precipitation Change and Drought-Flood Evolution in North China

The issue of water shortage and related eco-environmental degradation in North China is one of the major emerging problems in China. Precipitation is the most important factor for water resources. Based on the historical series of instrumental data of annual precipitation obtained from 25 gauging stations and a long-term historical drought-flood grade dataset during the period of 1470-2000 obtained from 15 gauging stations in North China, the character of precipitation variability was analyzed by means of power spectrum and continuous wavelet transform. It was found that the precipitation was characterized by obvious seasonal changes, quasi-biennial oscillation, and quasi-19-year interdecadal periodicity. The M-K test results showed that abrupt changes in annual precipitation occurred around 1914 and 1964. As for the historical flood/dryness grade time series, it was characterized by the 4-5-year ENSO mode interannual oscillation, the quasi-10-year and quasi-24-year interdecadal variabilities and 50-80-year centurial periodicity.