The ETKF rescaling scheme in HIRLAM

被引：10

作者：

Bojarova, Jelena ^{[1
]}

Gustafsson, Nils ^{[2
]}

Johansson, Ake ^{[2
]}

Vignes, Ole ^{[1
]}

机构：

[1] Norwegian Meteorol Inst, NO-0313 Oslo, Norway

[2] Swedish Meteorol & Hydrol Inst, SMHI, SE-60176 Norrkoping, Sweden

来源：

TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY | 2011年 / 63卷 / 03期

关键词：

TRANSFORM KALMAN FILTER; DATA ASSIMILATION; PART I; ENSEMBLE; IMPLEMENTATION; INTERPOLATION;

D O I：

10.1111/j.1600-0870.2011.00513.x

中图分类号：

P4 [大气科学（气象学）];

学科分类号：

0706 ; 070601 ;

摘要：

The ETKF rescaling scheme has been implemented into the HIRLAM forecasting system in order to estimate the uncertainty of the model state. The main purpose is to utilize this uncertainty information for modelling of flow-dependent background error covariances within the framework of a hybrid variational ensemble data assimilation scheme. The effects of rank-deficiency in the ETKF formulation is explained and the need for variance inflation as a way to compensate for these effects is justified. A filter spin-up algorithm is proposed as a refinement of the variance inflation. The proposed spin-up algorithm will also act to prevent ensemble collapse since the ensemble will receive 'fresh blood' in the form of additional perturbation components, generated on the basis of a static background error covariance matrix. The resulting ETKF-based ensemble perturbations are compared with ensemble perturbations based on targeted singular vectors and are shown to have more realistic spectral characteristics.

引用

页码：385 / 401

页数：17

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