Comparison of United States and Russian complex terrain diffusion models developed for regulatory applications

The theoretical bases and computational techniques are presented for U.S. and Russian complex terrain diffusion models developed for regulatory applications. While the U.S. model is based on the modified Gaussian diffusion model, the Russian model is based on the analytical approximation of results of the joint numerical integration of the equation of atmospheric diffusion and the system of equations of hydrothermodynamics for the atmospheric boundary layer over curvilinear, thermally inhomogeneous underlying surfaces. The Russian and U.S. models are compared with measured concentrations from the Cinder Cone Butte, Idaho, field measurement program. The Russian model is shown to have an error of about 25% for evaluation of upper percentiles of the probability distribution function, whereas the U.S. model yields an error of about 15% for mean values of concentrations. Additional comparisons are made between the U.S. model and four other field measurement programs, and between the Russian model and U.S. EPA wind-tunnel simulations. It is concluded that each of the models provides appropriate solutions to the principal problems formulated by their respective national legislation and regulatory acts.