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A multivariate balance operator for variational ocean data assimilation
Author(s) -
Weaver A. T.,
Deltel C.,
Machu E.,
Ricci S.,
Daget N.
Publication year - 2005
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1256/qj.05.119
Subject(s) - data assimilation , operator (biology) , multivariate statistics , transformation (genetics) , mathematics , assimilation (phonology) , uncorrelated , computer science , meteorology , statistics , physics , biochemistry , chemistry , linguistics , philosophy , repressor , transcription factor , gene
It is common in meteorological applications of variational assimilation to specify the error covariances of the model background state implicitly via a transformation from model space where variables are highly correlated to a control space where variables can be considered to be approximately uncorrelated. An important part of this transformation is a balance operator which effectively establishes the multivariate component of the error covariances. The use of this technique in ocean data assimilation is less common. This paper describes a balance operator that can be used in a variable transformation for oceanographic applications of three‐ and four‐dimensional variational assimilation. The proposed balance operator has been implemented in an incremental variational data assimilation system for a global ocean general‐circulation model. Evidence that the balance operator can explain a significant percentage of background‐error variance is presented. The multivariate analysis structures implied by the balance operator are illustrated using single‐observation experiments. Copyright © 2005 Royal Meteorological Society