Determination of Optimal Diffusion Coefficients in Lake Zirahuén through a Local Inverse Problem

In this study, optimal diffusion coefficients for Lake Zirahuén, Mexico, were found under particular conditions based on images taken with a drone of a dye release experiment. First, the dye patch concentration was discretized using image processing tools, and it was then approximated by an ellipse, finding the optimal major and minor axes. The inverse problem was implemented by comparing these observational data with the concentration obtained numerically from the 2D advection–diffusion equation, varying the diffusion tensor. When the tensor was isotropic, values of K 11 = K 22 ≈ 0.003 m 2 / s were found; when nonequal coefficients were considered, it was found that K 11 ≈ 0.005 m 2 / s and K 22 ≈ 0.002 m 2 / s , and the cross-term K 12 influenced the results of the orientation of the ellipse. It is important to mention that, with this simple technique, the parameter estimation had consequences of great importance as the value for the diffusion coefficient was bounded significantly under particular conditions for this site of study.