Sources of uncertainty in atmospheric dispersion modeling in support of Comprehensive Nuclear–Test–Ban Treaty monitoring and verification system

Abstract

The uncertainty in the atmospheric transport and dispersion modeling (ATM), used in support of the Comprehensive Nuclear–Test–Ban Treaty (CTBT) monitoring and verification system, is a critical issue, and it may have political consequences. The uncertainty in ATM can be reduced, but it cannot be eliminated at all for many reasons: the impossibility of error-free measurements, the discretization of the continuous atmospheric flow in measuring and modeling, there is no analytical solution of Navier-Stokes equations which governs the atmospheric motion, the stochastic nature of the radioactive processes, and the ill-posedness of the inverse modeling. Therefore, our knowledge about the atmospheric state is incomplete and inexact. Thus, any representation of the atmospheric state is just an approximation of the unknown true state of the atmosphere, even if all available observations, the best data assimilation scheme, and the best coupled Earth-System models are used. Therefore, the quantification of the uncertainty should be an essential part of the operational ATM in CTBT's RN monitoring and verification procedures. The current work reviews the different sources of uncertainty included in these procedures, and it discusses the available methods to quantify these uncertainties regarding the current state-of-the-art and future development in the atmospheric modeling and data assimilation.