## Abstract In multivariate time series, estimation of the covariance matrix of observation innovations plays an important role in forecasting as it enables computation of standardized forecast error vectors as well as the computation of confidence bounds of forecasts. We develop an online, nonβite
Forecast covariances in the linear multiregression dynamic model
β Scribed by Catriona M. Queen; Ben J. Wright; Casper J. Albers
- Book ID
- 102214480
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 285 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0277-6693
- DOI
- 10.1002/for.1050
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β¦ Synopsis
Abstract
The linear multiregression dynamic model (LMDM) is a Bayesian dynamic model which preserves any conditional independence and causal structure across a multivariate time series. The conditional independence structure is used to model the multivariate series by separate (conditional) univariate dynamic linear models, where each series has contemporaneous variables as regressors in its model. Calculating the forecast covariance matrix (which is required for calculating forecast variances in the LMDM) is not always straightforward in its current formulation. In this paper we introduce a simple algebraic form for calculating LMDM forecast covariances. Calculation of the covariance between model regression components can also be useful and we shall present a simple algebraic method for calculating these component covariances. In the LMDM formulation, certain pairs of series are constrained to have zero forecast covariance. We shall also introduce a possible method to relax this restriction.βCopyright Β© 2008 John Wiley & Sons, Ltd.
π SIMILAR VOLUMES
## Abstract This article reviews a range of leading methods to model the background error covariance matrix (the **B**βmatrix) in modern variational data assimilation systems. Owing partly to its very large rank, the **B**βmatrix is impossible to use in an explicit fashion in an operational setting