In variational data assimilation (VDA) for meteorological and/or oceanic models, the assimilated fields are deduced by combining the model and the gradient of a cost functional measuring discrepancyâ€¦ (More)

In the present paper we consider a 2-D shallow-water equations (SWE) model on a Î²-plane solved using an alternating direction fully implicit (ADI) finite-difference scheme on a rectangular domain.â€¦ (More)

The Maximum Likelihood Ensemble Filter (MLEF) equations are derived without the differentiability requirement for the prediction model and for the observation operators. The derivation reveals that aâ€¦ (More)

A new ADI method is proposed for the approximate solution of the shallow-water equations. Based on a perturbation of a linearized Crank-Nicolson-type discretization, this method is algebraicallyâ€¦ (More)

Particle filter (PF) is a fully non-linear filter with Bayesian conditional probability estimation, compared here with the well-known ensemble Kalman filter (EnKF). A Gaussian resampling (GR) methodâ€¦ (More)

A Galerkin finite-element model of the shallow-water equations on a limited domain is presented. The evolutionary equations of continuity and momentum are coupled at each time step using anâ€¦ (More)

Optimal control theory of partial di erential equations has emerged as a new way to attack problem of D atmospheric oceanic data assimilation problems These variational techniques attempt to achieveâ€¦ (More)

Strategies to achieve order reduction in four dimensional variational data assimilation (4D-Var) search for an optimal low rank state subspace for the analysis update. A common feature of theâ€¦ (More)

A wavelet regularization approach is presented for dealing with an ill-posed problem of adjoint parameter estimation applied to estimating inflow parameters from down-flow data

Order reduction strategies aim to alleviate the computational burden of the four-dimensional variational data assimilation by performing the optimization in a low-order control space. The properâ€¦ (More)