Articles | Volume 18, issue 20
https://doi.org/10.5194/gmd-18-7815-2025
https://doi.org/10.5194/gmd-18-7815-2025
Development and technical paper
 | 
27 Oct 2025
Development and technical paper |  | 27 Oct 2025

Multigrid beta filter for faster computation of ensemble covariance localization

Sho Yokota, Miodrag Rancic, Ting Lei, R. James Purser, and Manuel S. F. V. De Pondeca

Cited articles

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Short summary
Covariance localization to mitigate sampling error of ensemble-based forecast error covariances is one of the main parts of the calculation in ensemble-variational data assimilation for the atmosphere. This study clarifies that the multigrid beta filter-based localization makes it several times faster than the conventional recursive filter-based one without significantly changing the analysis if a coarser filter grid is applied and filters except for the coarsest resolution are omitted.
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