The characteristics of background error covariances have a close relationship with the local meteorological features.In order to get a better understanding for the characteristics of background error covariances in East China and the Tibetan Plateau,the major parameters of background error covariances,such as variable correlation coefficients,eigenvalues,eigenvectors and characteristic length scales,were compared and analyzed using one month series of numerical forecast fields in summer based on the latest model of multivariate background error covariances.Results show that the relationships between different variables in the Tibetan Plateau are more notable than those in East China.In the Tibetan Plateau,the deviation of background error is more obvious and the local property of atmospheric characteristics are stronger.In terms of data assimilation in the Tibetan Plateau,the observations occupy more weight and smaller influencing area,which puts forward higher requirements on observations in the Tibetan Plateau.