近50年江苏省粮食产量变化的小波分析

粮食产量变化关系到国家和地区的粮食安全问题。以往对粮食产量变化的研究多集中在单时间尺度上，对多时间尺度的研究很少。以小波诊断技术为基础，对近50年江苏省粮食产量变化进行了多时间尺度的分析。研究结果表明：①近50多年江苏省粮食产量生产大致经历了5个阶段；②江苏省粮食产量变化具有明显的5年、13年和25年的特征时间尺度和相应的周期性变化特征；同时特征时间尺度有逐步增加的趋势，即江苏省的粮食产量变化渐趋稳定；③小波方差分析发现江苏省粮食产量变化具有13年和25年的主要周期，并以25年周期最为显著； ④综合三个时间尺度上小波系数的演变趋势发现，无论是大尺度还是小尺度上，在未来的一段时间内，江苏省都将进入新的一轮粮食减产时期。针对粮食产量变化的这一趋势，进行了原因分析，并提出相应的建议。

WAVELET ANALYSIS OF GRAIN OUTPUT IN JIANGSU PROVINCE DURING THE LAST 50 YEARS

The study of the grain output changes is mainly based on the single scale before, and few is on the multiple time scales. So the wavelet analysis has been used to analyze the grain output in Jiangsu Province during the Last 50 years at multiple time scales. The results show :① The grain output in Jiangsu has gone through five stages. ②The grain output has 3 year,13 year and 25 year characteristic time scales , and the time scales tend to become longer and it indicates that the changes of grain output of Jiangsu Province become slow. ③The grain output has 13 year and 25 year periods and the 25 year period is especially outstanding from the wavelet variances analysis .④Whether at the big scale or at small scale, the grain output of Jiangsu Province will reduce in the recent years on the base of the analysis of the fig of the wavelet coefficients. We have analysed the reason and have proposed some suggestion on how to guarantee the security of grain output of Jiangsu province.