Evaluation of the uncertainty in the ozone flux effect modelling: From the experiments to the dose-response relationships

The paper is an attempt to assess the uncertainty involved in the modelling process of deriving the flux effects relationships from the experimental evidences of a network of coordinated experiments on ozone and vegetation (the LRTAP Convention's ICP Vegetation). Ten modelling steps have been described and analysed. Even if some steps were more critical than others in introducing uncertainty, the whole modelling process seems to be quite robust. The stomatal dose calculation is precise enough when performed on long time periods (e.g. growing season). The main sources of inaccuracy for the stomatal dose calculation can be ascribed to the adoption of different schemes for the calculation of ozone concentration at leaf level (7-10%). The estimation of the ozone effects on vegetation, and particularly the derivation of the plant's response at the theoretical zero-ozone dose, proves to be the main source of uncertainty of the whole process (up to 17%). In order to improve the precision of this step an increased number of ozone treatments and replicates in the experiments is recommended, while a harmonization/standardization of the calculation algorithm is required to improve the accuracy of the dose calculation. (C) 2012 Elsevier Ltd. All rights reserved.