Abstract: This paper presents an estimate of the Cressman term that appears in the divergent barotropic model as a corrector of planetary-wave retrogression. In contrast with earlier studies, the term varies as a function of ...

Abstract: When the height of the 500 mb surface is represented with the aid of empirical orthogonal functions, the residual should consist mainly of analysis error. However, unlike the analysis error, the residual is larger over ...

Abstract: A method of computing autocorrelation fields with the aid of empirical orthogonal functions (EOF) is applied. The isotropic parts of the fields are separated, and a one-parameter model of the isotropic autocorrelation field ...

Abstract: The structure of the analysis error field of the 500 mb height north of 20°N was estimated from the differences between analyses issued by two different centers. The resulting variance field is very similar to that computed ...

Abstract: A rapid method of computing the EOFs for a problem with a large covariance matrix is presented. The resulting EOFs are not the ?true? ones because they do not guarantee that the maximum variance is explained in the dependent ...

Abstract: The spatial autocorrelation of the error of the ECMWF 24-h forecast of 500 mb geopotential height during 1980?83, hereafter referred to as the ?forecast error,? is studied. The leading EOF of the forecast error describes ...

Abstract: The yearly variances of the analysis error of the 500 mb height north of 20°N are estimated from analyses covering the period 1946?79. A new method is presented. The error variances are computed directly from the analyses ...

Abstract: Different methods of studying the random error variance of 500 mb geopotential height analyses are discussed and applied. It has not been possible to show that the random errors of the operational analyses during the FGGE ...

Abstract: The smoothing of 500 mb geopotential analyses has been studied by comparing the variances of the EOF components. As an indicator of the total analysis error, the sums of the smoothing variances and random error variances ...

Abstract: The chaotic structure of two-dimensional atmospheric flow is illustrated. It is shown that certain errors in numerical approximations can Prevent the correct prediction of chaotic processes. This is the case when the ...