集合预报方法的全局研究

应用一个最大简化的6变量非线性模式,引入胞映射全局分析方法,研究初值误差范围内不同扰动对预报结果的影响。在获得对其全局认识的基础上,再通过理论研究与预报实践证明,集合预报方法确能改进预报。理论研究表明,可以求出最佳集合样本数,而且由模式预报试验得到的最佳集合样本数与理论结果是一致的。另外,观测精度、预报精度以及模式状态变量的个数对最佳集合样本数有着不同的影响。

A GLOBAL STUDY ON ENSEMBLE PREDICTION METHOD

By introducing cell to cell mapping method of global analysis and using a six variable nonlinear model, the influence of different perturbation within observational error on prediction is studied first in this paper. Based upon such a global understanding, it is proved that ensemble prediction method does improve the prediction by both theoretical research and forecasting practice. The optimal number of ensemble samples can be obtained theoretically, and it is consistent with the result of model forecasting experiment. Moreover, the observational precision, forecasting precision, and variable number of a model have different influences on the optimal number of ensemble samples.