【摘要】 利用华北地区２６ 个站的１９５１ ～１９９７ 年月降水量（ Ｐ） 和月平均气温（ Ｔ） 资料，用高桥浩一郎的蒸发计算公式计算了地面蒸发量（ Ｅ） ，并通过Ｍｏｒｌｅｔ 小波变换法分析了华北地区的水资源各分量（ Ｐ，Ｅ 及可利用降水Ｐ－ Ｅ） 的时间频率的多层次结构和突变特征。更多还原

【Abstract】 The characteristics of multiple time scales and the feature of abrupt change for the every component of the water resources (precipitation P , evaporation E and utilizable precipitation P-E ) have been analyzed by means of the Morlet wavelet transformation method. The data sets for study are the monthly precipitation ( P ) and temperature ( T ) from 1951 to 1997 at 26 stations over North China. The evaporation (E) is calculated by Koichiro’s evaporation equation.更多还原