Open AccessUncertainty in a chemistry‐transport model due to physical parameterizations and numerical approximations: An ensemble approach applied to ozone modeling
Author(s) -
Mallet Vivien,
Sportisse Bruno
Publication year - 2006
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2005jd006149
Subject(s) - polyphemus , robustness (evolution) , closure (psychology) , turbulence , statistical physics , grid , computer simulation , ensemble forecasting , mathematics , meteorology , computer science , chemistry , simulation , physics , geology , limulus , paleontology , biochemistry , geometry , economics , market economy , gene
This paper estimates the uncertainty in the outputs of a chemistry‐transport model due to physical parameterizations and numerical approximations. An ensemble of 20 simulations is generated from a reference simulation in which one key parameterization (chemical mechanism, dry deposition parameterization, turbulent closure, etc.) or one numerical approximation (grid size, splitting method, etc.) is changed at a time. Intercomparisons of the simulations and comparisons with observations allow us to assess the impact of each parameterization and numerical approximation and the robustness of the model. An ensemble of 16 simulations is also generated with multiple changes in the reference simulation in order to estimate the overall uncertainty. The case study is a four‐month simulation of ozone concentrations over Europe in 2001 performed using the modeling system Polyphemus. It is shown that there is a high uncertainty due to the physical parameterizations (notably the turbulence closure and the chemical mechanism). The low robustness suggests that ensemble approaches are necessary in most applications.