Abstract: Since Deardorff (1966) derived the counter-gradient term contribution [1], many researchers have tried a good representation for this term [2-4]. As pointed out by Campos Velho et al. [5] an inverse problem methodology could be used to identify this property. Here, a Eulerian pollutant dispersion formulation is used as forward model. The inverse analysis is performed minimizing an objective function: the square difference between experimental and model data added to a regularization function. Two regularization functions are used, second-order maximum entropy [6, 7] and Tikhonov regularization of second-order. Synthetic noise data are used as experimental data.

[1] J.W. Deardorff (1966): "The Counter-gradient Heat Flux in the Lower Atmosphere and in the Laboratory", Journal of Atmospheric Sciences, 23 (5), 503-506.

[2] A.A.M. Holtslag, C.-H. Moeng (1991): "Eddy Diffusivity and Countergradient Transport in the Convective Boundary Layer", Journal of Atmospheric Sciences, 48 (14), 1690-1698.

[3] J.W.M. Cuijpers, A.A.M. Holtslag (1998): "Impact of Skewness and Nonlocal Effects on Scalar and Boundancy Fluxes in Convective Boundary Layers", Journal of Atmospheric Sciences, 55 (2), 151-162.

[4] H.F. Campos Velho, A.A.M. Holtslag, G.A. Degrazia, R.A. Pielke (1998): "New Parameterizations in RAMS for Vertical Turbulent Fluxes", Department of Atmospheric Sciences, Colorado State University, Fort Collins (CO), USA.

[5] H.F. Campos Velho, M.R. de Moraes, F.M. Ramos, G.A. Degrazia, D. Anfossi (2000): "An Automatic Methodology for Estimating Eddy Diffusivity from Experimental Data", Il Nuovo Cimento, 23 C (1), 65-84.

[6] F.M. Ramos, H.F. Campos Velho, J.C. Carvalho, N.J. Ferreira (1999): "Novel Approaches on Entropic Regularization", Inverse Problems, 15 (5), 1139-1148.

[7] W.B. Muniz, F.M. Ramos, H.F. Campos Velho (2000): "Entropy- and Tikhonov-based Regularization Techniques Applied to the Backwards Heat Equation", Computers & Mathematics with Applications, 40(8/9), 1071-1084.