【摘要】 采用Morlet小波变换分析法,分析了烟台市1949～2003年粮食产量变化特征,结果表明:建国以来,烟台市粮食产量总体上呈不断上升趋势,大致经历了4个发展阶段;烟台市粮食年产量变化具有明显的3～9、10～25和18～32年3类特征时间尺度和相应的周期变化特征;烟台市粮食年产量变化具有6和21年的主周期,并以21年周期最为明显;在未来一段时间内,烟台市粮食年产量将会进入相对增产时期。更多还原

【Abstract】 In this paper,the multiple time scales characteristics of grain food output in Yantai from 1949 to 2003 were studied based on the wavelet transformation. The results showed that the grain food output variation in Yantai from 1949 to 2003 was increasing including four stages; the grain food output had characteristic of the time scales and the characteristics of periods variation of 3~9,10~25 and 18~32 years,respectively; the variation of grain food output had 6-year and 21-year periods and the 21-year period was especially outstanding and based on the wavelet coefficients of 6-year and 21-year characteristic time scales,the grain food output in Yantai will increase in recent years.更多还原