基于NCEP/NCAR提供的1950-2000年月平均海温场资料,首先用EOF方法对海温场序列进行时、空分解,在考虑相邻时段位势场空间模态基本稳定的前提下,引入动力系统重构思想,以EOF分解的空间模态时间系数序列作为动力模型变最,用遗传算法全局搜索和并行计算优势,进行了模型参数的优化反演,建立了EOF分解时间系数的非线性预报模型。通过模型积分和EOF时、空重构,实现了海温场的中长期预报。试验结果表明,在1—6月时效预报上,模型预报海温场与实际海温场非常吻合;对于7 15月时效的预报,尽管模型预报的海温场与实际海温场存在一些出入,但基本构型大致相符,特别是对12月以上的海温场形态和范围仍然能较为准确地描述。所有时效的预报结果均能对1997年的El Nino事件特征有不同程度的描述。该研究方法为海温场以及El Nino/La Nina事件的预报提供了一种新的思路,文中提出的反演热带太平洋海温场与El Nino/LaNina的动力统计模型的研究思想和技术途径,在热带太平洋海温场的预测试验中(特别是中、长期预报)表现出良好的预报效果,为热带太平洋海温场及其异常的El Nino/La Nina事件的中、长期预报提供了有益的研究和参考方法。
Based on 1950-2000 month-average SST field from the NCEP/ NCAR reanalysis data,SST field series are spacetime decompounded using the EOF method.With the hypothesis of EOF space-mode being stable and unchangeable assumed and the dynamic system reconstruction idea introduced,the EOF time coefficient series is taken as the dynamical statistic model variable and the dynamical model parameters are optimized and retrieved to establish a non-linear dynamic statistic model of EOF separated time coefficient series.By the model lime integral and EOF time-space reconstruction,a mid-long-range forecast of SST field is performed.The test result shows that to the 1-6 month forecast,the SST field forecasted by our model are very similar to the actual SST fields to 7- 15 month forecast,the basic conformation are approximately the same although the SST field forecasted by our model has some differences from the actual SST field;in particular,the configuration of the SST field more than 12 months can be accurately depicted.The forecast results for all the leading times can describe the characteristic of the El Nino in 1997 to some extent.The investigative method suggested a new approach to forecasting SST field and showed a better result.This nethodology and technique suggested in this paper for retrieving the parameters of the dynamical model of the SST field of the tropical Pacific Ocean El Nino/La Nina events show nice effect on the forecasting SST field of the tropical Pacific Ocean(especially in the medium and long term),offering the nice investigative search and method of the SST field of the tropical Pacific Ocean and the medium and long term forecast of the exceptional El Nino/La Nina events.