Guidance on how to improve vertical covariance localization based on a 1000-member ensemble
نویسندگان
چکیده
Abstract. The success of ensemble data assimilation systems substantially depends on localization, which is required to mitigate sampling errors caused by modeling background error covariances with undersized ensembles. However, finding an optimal localization highly challenging, as covariances, errors, and appropriate depend various factors. Our study investigates vertical based a unique convection-permitting 1000-member simulation; correlations serve truth for examining their error. We discuss requirements deriving empirical (EOL) that minimizes the in 40-member subsample respect reference. analysis covers temperature, specific humidity, wind pressure levels. Results suggest should several aspects, such respective variable, level, or correlation type (self- cross-correlations). Comparing common distance-dependent approaches highlights suitable functions bears substantial room improvement. Furthermore, we examine achieving positive semi-definiteness covariance hardly affect reduction. Finally, gain combining different adaptive statistical correction.
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ژورنال
عنوان ژورنال: Nonlinear Processes in Geophysics
سال: 2023
ISSN: ['1607-7946', '1023-5809']
DOI: https://doi.org/10.5194/npg-30-13-2023