福州“20型”秋季低温的周期图分析及其应用研究
Study on the Analysis of "Type 20" periodic Pattern of Low Temperature during Autumn Season in Fuzhou and Its Application
-
摘要: 本文以日平均气温连续三天以上小于20.0℃作为出现“20型”秋季低温的指标,通过对福州1951—1989年历年秋季低温初日的周期图分析,建立了周期图模式Ŷi=50.231+5.037cos((π/9)ti)-2.831sin((π/9)ti),分析了福州秋季低温的变化趋势及其对晚稻生产的影响。Abstract: Using the average daily temperature which is less than 20℃ for consecutive 3 days or more as the norm occuring "type 20" low temperature during autumn season, a periodic pattern modelled as Yi = 50.231+ 5.037Cosπ/9ti - 2.831Sinπ/9ti has been established via through the analysis of periodic pattern of initial days during autumn season from 1951 to 1989 in Fuzhou area. The dynamic change of low temperature and its influence on the production of late rice during autumn season in Fuzhou area has been analysed according to the model.