用方差分析法预测濮阳市冬小麦播种期降水量趋势

使用1971--2000年濮阳市冬小麦播种期降水量资料，采用方差分析法，按不同长度周期进行排列，求出各个周期的F值，进行F检验定出第一周期，其位相值为第一周期的第一次值。将原序列减去第一周期的位相值作为新序列1，对新序列1再进行不同长度周期排列，求出各个周期的F值，再进行F检验定出第二周期。对第一、二周期进行稳定性检查，采用经稳定后的第一、二周期的第2次值各自外推，求出预报初值，计算出剩余方差，建立预报方程，进而可计算出降水量预报值。经回代检验，历史拟合率为30／30=100％；2001—2005年试报准确率为4／5=80％。

Forecast Precipitation Tendency of Winter Wheat during Seeding Period in Puyang Adopting Variance Analysis Method

Using precipitation data of winter wheat during seeding period in Puyang, adopting variance analysis method, we arrange the data in different cycles and calculate the F value. We confirm the first cycle through F test; the phase value is the first value of the first cycle. The phase value of the first cycle subtracts from source sequence as new sequence 1. And then we do the same thing to the new sequence 1 and confirm the second cycle. The stability examination is carried to the first and second cycle; then we get predictive initial value via extrapolation, and calculate residual variance, found predictive e- quation, calculate precipitation forecast value. The historical fitting rate is 100% and forecast accuracy rate is 80% from 2001 to 2005.