Original Research Papers
Determination of optimal nudging coefficients
Authors:
- P. A. VidardEmail P. A. Vidard
- F.-X. Le Dimet
- A. Piacentini
Abstract
A four-dimensional variational assimilation (4D-Var) scheme is now widely used by meteorological centres in a operational way. However, most of these applications do not take account of model error. Indeed, the classical 4D-Var with imperfect model formulation is unaffordable for current computational means. This paper presents a low-cost method for dealing with model errors in 4D variational assimilation. This method can be formally compared to a Kalman filter. This new scheme is tested on two configurations: first on a Burger equation, which allows one to calibrate the method, and second on a more relevant shallow-water equations model, both in a twin experiment framework. It is shown that, compared to classical 4D-Var results, this method provides a noticeable improvement.
- Year: 2003
- Volume: 55 Issue: 1
- Page/Article: 1-15
- DOI: 10.3402/tellusa.v55i1.14576
- Submitted on 28 May 2001
- Accepted on 31 Jul 2002
- Published on 1 Jan 2003
- Peer Reviewed