基于Z指数的河北省旱涝多尺度变化特征

Multi-time scale characteristics of drought and flood based on Z index in Hebei province

利用1961—2009年京、津、冀73个气象站降水资料,计算降水Z指数,采用趋势分析、小波分析等方法,对河北省旱涝特征进行了分析。结果表明:近49 a来,河北省年降水Z指数呈下降趋势,并存在多时间尺度变化特征,具有7、9 a和15 a尺度的周期。夏季降水Z指数呈下降趋势,存在15 a显著的变化周期;冬、春季和秋季的降水Z指数均呈上升趋势,10—11 a的周期震荡明显。

Based on the precipitation data from 73 weather stations in Beijing,Tianjin and Hebei province from 1961 to 2009,the characteristics of drought and flood were analyzed with methods of a trend analysis and a wavelet analysis.The results indicate that Z index of the annual precipitation is in a decreasing trend in recent 49 years and there exists multi-time scale characteristics.The cycles are 7years,9 years and 15 years.Z index of summer precipitation is also in a decreasing trend and its cycle is 15 years,while Z indices of other seasons are in increasing trends and the significant cycles are 10-11 years.