Through analyzing problem of wavelet analysis,the annual runoff time series from 1956 to 2000 of Hejin hydrological station in Fen River are decomposed into multiple time-scale series with EMD method.

• 针对小波分析的不足之处,运用EMD法对汾河河津水文站还原后的天然径流量时序进行多时间尺度分析,并揭示了各分量的趋势变化及影响因素。