Abstract: Inverse radiative transfer problems have several relevant applications, in different areas such as environmental sciences, engineering and medicine. Some outstanding examples are parameter anf function estimation for global climate models, hydrologic optics and medical tomography. Several heuristics that mimic natural behaviours have been proposed for the solution of optimization problems. In particular some algorithms, classified within the swarm intelligence, are based on social insects, like bees, ants, etc. observation. In the late nineties the Ant Colony System (ACS) was applied successfully for the solution of combinatorial optimization problems, and more recently it has been proposed for the solution of some specific inverse problems associated with the estimation of real parameters.

Here we present an implementation of the ACS for the solution of the inverse radiative transfer problem of radiative properties estimation in a one dimensional plane-parallel medium. In this approach it is required the solution of the direct radiative transfer problem modelled by the linear version of the Boltzmann equation. For that purpose we use a discrete ordinates method combined with the finite difference method. Some general strategies are proposed and discussed for the ACS implementation for the estimation of the optical thickness, single scattering albedo, and diffuse reflectivities. Test case results demonstrate the feasibility of the use of the proposed methodology.