An analysis of error propagation in AERMOD lateral dispersion using Round Hill II and Uttenweiller experiments in reduced averaging times

Abstract

ABSTRACTDispersion modelling was proved by researchers that most part of the models, including the regulatory models recommended by the Environmental Protection Agency of the United States (AERMOD and CALPUFF), do not have the ability to predict under complex situations. This article presents a novel evaluation of the propagation of errors in lateral dispersion coefficient of AERMOD with emphasis on estimate of average times under 10 min. The sources of uncertainty evaluated were parameterizations of lateral dispersion (), standard deviation of lateral wind speed () and processing of obstacle effect. The model’s performance was tested in two field tracer experiments: Round Hill II and Uttenweiller. The results show that error propagation from the estimate of directly affects the determination of , especially in Round Hill II experiment conditions. After average times are reduced, errors arise in the parameterization of , even after observation assimilations of , exposing errors on Lagrangian Time Scale parameterization. The assessment of the model in the presence of obstacles shows that the implementation of a plume rise model enhancement algorithm can improve the performance of the AERMOD model. However, these improvements are small when the obstacles have a complex geometry, such as Uttenweiller.