Ertel potential vorticity inversion using a digital filter initialization method
✍ Scribed by Philippe Arbogast; Karine Maynard; Fabien Crepin
- Book ID
- 104565015
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 305 KB
- Volume
- 134
- Category
- Article
- ISSN
- 0035-9009
- DOI
- 10.1002/qj.283
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✦ Synopsis
Abstract
A new Ertel‐potential‐vorticity inversion method is proposed and tested in the framework of a low‐order model as well as in Météo France's operational primitive‐equation spectral model, ARPÈGE. The potential‐vorticity (PV) inversion procedure is designed so that its result lies within the subspace of model solutions, without the use of any explicit balance condition. The inversion is based on a variational problem in which one minimizes simultaneously the distance to the dynamical initialized solution following a digital‐filter method and the PV to be inverted. Since the inverted solution results from model backward and forward integrations, and not from a set of algebraic equations, it possesses a strong dynamical consistency. In the framework of a low‐order model, it is found that for small Rossby number, digital‐filter initialization lies between nonlinear normal‐mode initialization and quasi‐geostrophic methods. The method has also been successfully used to rebuild the non‐divergent flow, the temperature, and a significant part of the divergent flow, knowing only the three‐dimensional PV field and a boundary condition. Copyright © 2008 Royal Meteorological Society