中文摘要：

背景误差协方差是变分资料同化系统中的一个重要组成部分,能将观测信息从观测点传播到周围的模式格点和垂直层上.为了模拟背景误差协方差中水平误差函数的非均匀性和各向异性,提出了一种用正交小波变换模拟水平误差函数的新方法.试验结果表明：新方法能模拟出水平误差函数中固有的非均匀性和各向异性,极好地表示了背景误差协方差中固有的结构和特征.

英文摘要：

Background error covariance is an important part of variational data assimilation system, which is used to spread the observation information to other grid points and vertical levels of the model. In order to model the inhomogeneity and anisotropy in horizontal error functions of raw background error covariance, a new method is proposed to model horizontal error functions based on orthogonal wavelet transforms. The results of experiments show that the new method successfully modeled the heterogeneity and anisotropy included in the local correlation functions and depicted the structure and feature of raw covariance correctly.