“…Here, we consider the approximate deconvolution model, introduced by Adams and Stolz (see also previous studies); by following this scheme, we approximate the filtered bilinear terms as follows: where v and φ play the role of the variables u and θ , respectively, and the filtering operator G α is defined by the Helmholtz filter (see, eg, other studies; see also Bisconti and Catania for an analogous case involving an anisotropic horizontal filter), with and G α :=( I − α 2 Δ) −1 . Here, D N is the deconvolution operator, which is constructed using the Van Cittert algorithm (see, eg, Lewandowski) and is formally defined by …”