Variational data analysis with control of the forecast bias
We propose a methodology for the treatment of the systematic model error in variational data assimilation. The principle of the method is to add a systematic error correction term in the model equations and to include it in the variational assimilation control vector.
This method is applied to a simplified ocean circulation model in an identical twin experiment framework. It shows a noticeable improvement compared to the result of a classical variational assimilation scheme in which the systematic error is not corrected. The estimated systematic error correction term is sufficiently consistent with that needed by the model that it allows improvements not just to the analysis, but also during the forecast phase.
Document Type: Research Article
Affiliations: 1: Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique, 42, avenue Coriolis, 31057 Toulouse cedex, France 2: Laboratoire de Modélisation et Calcul. Université Joseph Fourier, BP 53 38041 Grenoble, France
Publication date: May 1, 2004