@misc{76869,
  author = {A.T. Weaver and C. Deltel and E. Machu and S. Ricci and N. Daget},
  title = {A multivariate balance operator for variational ocean data assimilation.},
  abstract = {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.},
  year = {2006},
  journal = {ECMWF Technical Memoranda},
  number = {491},
  pages = {19},
  month = {04/2006},
  publisher = {ECMWF},
  address = {Shinfield Park, Reading},
  url = {https://www.ecmwf.int/node/13007},
  doi = {10.21957/a1q77nvm8},
  language = {eng},
}