Assessment of possible transboundary transport: direct and inverse problems

Possible formulations of mathematical modeling problems intended for estimating transboundary transport are considered. Two approaches are possible. The first approach is related to direct modeling methods. It actually consists in obtaining forecasts of impurity distribution with all the necessary data to solve such problems. The second approach, using the methods of inverse modeling, makes it possible to obtain estimates of some functionals characterizing the desired solutions, for example, related to the search for possible sources of disturbances that led to transboundary transport. We develop both of these approaches based on the variational principle. Some remarks on both approaches are discussed.