Implications of the Form of the Ensemble Transformation in the Ensemble Square Root Filters
Implications of the Form of the Ensemble Transformation in the Ensemble Square Root Filters
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DOI:
10.1175/2007mwr2021.1
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发表时间:
2008-03
影响因子:
3.2
通讯作者:
P. Sakov;P. Oke
中科院分区:
文献类型:
--
作者:
P. Sakov;P. Oke
Abstract This paper considers implications of different forms of the ensemble transformation in the ensemble square root filters (ESRFs) for the performance of ESRF-based data assimilation systems. It highlights the importance of using mean-preserving solutions for the ensemble transform matrix (ETM). The paper shows that an arbitrary mean-preserving ETM can be represented as a product of the symmetric solution and an orthonormal mean-preserving matrix. The paper also introduces a new flavor of ESRF, referred to as ESRF with mean-preserving random rotations. To investigate the performance of different solutions for the ETM in ESRFs, experiments with two small models are conducted. In these experiments, the performances of two mean-preserving solutions, two non-mean-preserving solutions, and a traditional ensemble Kalman filter with perturbed observations are compared. The experiments show a significantly better performance of the mean-preserving solutions for the ETM in ESRFs compared to non-mean-preservi...