Document Type
Article
Publication Date
9-29-2009
Department
Marine Science
Abstract
A version of the reduced control space four-dimensional variational method (R4DVAR) of data assimilation into numerical models is proposed. In contrast to the conventional 4DVAR schemes, the method does not require development of the tangent linear and adjoint codes for implementation. The proposed R4DVAR technique is based on minimization of the cost function in a sequence of low-dimensional subspaces of the control space. Performance of the method is demonstrated in a series of twin-data assimilation experiments into a nonlinear quasigeostrophic model utilized as a strong constraint. When the adjoint code is stable, R4DVAR's convergence rate is comparable to that of the standard 4DVAR algorithm. In the presence of strong instabilities in the direct model, R4DVAR works better than 4DVAR whose performance is deteriorated because of the breakdown of the tangent linear approximation. Comparison of the 4DVAR and R4DVAR also shows that R4DVAR becomes advantageous when observations are sparse and noisy.
Publication Title
Monthly Weather Review
Volume
137
Issue
9
First Page
2966
Last Page
2978
Recommended Citation
Yaremchuk, M.,
Nechaev, D. A.,
Panteleev, G.
(2009). A Method of Successive Corrections of the Control Subspace in the Reduced-Order Variational Data Assimilation. Monthly Weather Review, 137(9), 2966-2978.
Available at: https://aquila.usm.edu/fac_pubs/1137
Comments
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