A variational approach for parameter estimation based on balanced proper orthogonal decomposition
KAUST DepartmentWater Desalination and Reuse Research Center (WDRC)
Biological and Environmental Sciences and Engineering (BESE) Division
Environmental Science and Engineering Program
Online Publication Date2018-10-25
Print Publication Date2019-02
Permanent link to this recordhttp://hdl.handle.net/10754/630613
MetadataShow full item record
AbstractThe adjoint method has been used significantly for parameter estimation. This requires a significant programming effort to build adjoint model code and is computationally expensive as cost of one adjoint simulation often exceeds several original model runs. The work proposed here is variational data assimilation based on balanced proper orthogonal decomposition (BPOD) to identify uncertain parameters in numerical models and avoids the implementation of the adjoint with respect to model input parameters. An ensemble of model simulations (forward and backward) is used to determine the model subspace while considering both inputs and outputs of the system. By projecting the original model onto this subspace an approximate linear reduced model is obtained. The adjoint of the tangent linear model is replaced by the adjoint of linear reduced model and the minimization problem is then solved in the reduced space at very low computational cost. The performance of the method are illustrated with a number of data assimilation experiments in a 2D-advection diffusion model. The results demonstrate that the BPOD based estimation approach successfully estimates the diffusion coefficient for both advection and diffusion dominated problems. The paper also proposes an efficient method for computing the observable subspace when the number of observations is large is also proposed.
CitationAltaf MU, McCabe MF (2019) A variational approach for parameter estimation based on balanced proper orthogonal decomposition. Computer Methods in Applied Mechanics and Engineering 344: 694–710. Available: http://dx.doi.org/10.1016/j.cma.2018.10.013.
SponsorsWe would like to thank the anonymous reviewers for the constructive comments. Research reported in this publication was supported by the King Abdullah University of Science and Technology (KAUST) .