Efficient nonlinear data assimilation using synchronisation in a particle filter

Pinheiro, F. R., Van Leeuwen, P. J. and Geppert, G. (2019) Efficient nonlinear data assimilation using synchronisation in a particle filter. Quarterly Journal of the Royal Meteorological Society, 145 (723). pp. 2510-2523. ISSN 1477-870X doi: 10.1002/qj.3576

Abstract/Summary

Current data assimilation methods still face problems in strongly nonlinear cases. A promising solution is a particle filter, which provides a representation of the state probability density function (pdf) by a discrete set of particles. To allow a particle filter to work in high-dimensional systems, the proposal density freedom is explored.We used a proposal density from synchronisation theory, in which one tries to synchronise the model with the true evolution of a system using one-way coupling, via the observations. This is done by adding an extra term to the model equations that will control the growth of instabilities transversal to the synchronisation manifold. In this paper, an efficient ensemble-based synchronisation scheme is used as a proposal density in the implicit equal-weights particle filter, a particle filter that avoids filter degeneracy by construction. Tests using the Lorenz96 model for a 1000-dimensional system show successful results, where particles efficiently follow the truth, both for observed and unobserved variables. These first test show that the new method is comparable to and slightly outperforms a well-tuned Local Ensemble Transform Kalman Filter. This methodology is a promising solution for high-dimensional nonlinear problems in the geosciences, such as numerical weather prediction.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/84056
Identification Number/DOI	10.1002/qj.3576
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > National Centre for Earth Observation (NCEO) Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Royal Meteorological Society
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