Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 2 6 2002 10.5194/acpd-2-2133-2002 http://www.atmos-chem-phys-discuss.net/2/2133/2002/ http://www.atmos-chem-phys-discuss.net/2/2133/2002/acpd-2-2133-2002.html http://www.atmos-chem-phys-discuss.net/2/2133/2002/acpd-2-2133-2002.pdf 2133 2150 2002-11-19 Adjoint backtracking for the verification of the Comprehensive Test Ban Treaty J.-P. Issartel J. Baverel Ecole Nationale des Ponts et Chaussées, Centre d’Enseignement et de Recherche Eau, Ville, Environnement, Champs sur Marne, France previously at: Commissariat à l’Energie Atomique, DASE, Bruyères le Châtel, France An international monitoring system is being built as a verification tool for the Comprehensive Test Ban Treaty. Forty stations will measure on a worldwide daily basis the concentration of radioactive noble gases. The paper introduces, by handling preliminary real data, a new approach of backtracking for the identification of sources after positive measurements. When several measurements are available the ambiguity about possible sources is reduced significantly. As an interesting side result it is shown that diffusion in the passive tracer dispersion equation is necessarily a self-adjoint operator.