70 Ozone Risk for Douro Vineyards in Present and Future Climates
441
were selected to simulate the present climate, 2049 and 2064 for the mid-term future
climate and the years 2096 and 2097 for the long-term future climate. The air quality
simulations for the future climate were two-fold: one was done considering climate
change only, i.e. emissions were kept the same as in present climate simulations, to
assess the contribution of meteorological variables alone on future O 3 concentrations
levels; the other also included future emissions assessing future O 3 concentrations
resulting from both contributions (meteorology and emissions).
To evaluate the risk of Douro vineyard exposure to O 3 the legislated exposure
indicator AOT40 (accumulated concentration of ozone above 40 ppb) was calculated
as an average of AOT40 values for the simulated years, by scenario. The deposition
level results were based on the total O 3 dry deposition accumulated over May to July,
the same period established in the Air Quality Framework Directive 2008/50/CE for
the calculation of the AOT40 indicator. The assessment of the potential damage in
terms of productivity and quality was done through the application of the exposureresponse functions calculated by Soja et al. [5] in their three-year experimental study
on the effects of long-term ozone exposure in grapevines. For the purpose of this
work, the function applied was the one calculated in the last year of the experiment
and thus the one that represents the most damage in vines.
70.3 Modelling Results
A summary of the modelling results is presented in Fig. 70.1, which includes the
results for present climate, and for long-term future climate, considering only the
climate change and considering climate and emissions changes. The delimitated area
in the maps is the DDR.
When considering the climate change impact on O 3 concentration, the modelling
results show an averaged increase of 7% in the AOT40 levels, which is reflected
in a 9 and 7% decrease in productivity and quality. When emission projections are
applied, the AOT40 levels drop approximately 8%, reflecting an increase of 8% in
productivity and 7% in quality. These results indicate that the reduction in AOT40
levels is mostly driven by emissions reduction, which is in agreement with Klingberg
et al. [3] conclusions. Nevertheless, the target value for the protection of vegetation
(18,000 µg m
−3 h) is still exceeded over all the DDR.
When discussing these outcomes it is important to remember that although AOT40
is an important indicator for assessing the risk of vegetation exposure to ozone, it is
known that it has some limitations. For instance, it does not take into consideration
the uptake of ozone by the plants, which depends on the stomatal flux, overestimating
the potential damages. Furthermore, applying Soja et al. [5] functions brings also
uncertainty to the results, since the variety and age of the vines can respond differently
to ozone exposure [6].
Regarding dry O 3 deposition levels, both future simulation scenarios show a
decrease in deposition of almost 50% when compared with the present climate simulations. This indicates that, as opposed to AOT40 levels, the dry deposition is mainly
441
were selected to simulate the present climate, 2049 and 2064 for the mid-term future
climate and the years 2096 and 2097 for the long-term future climate. The air quality
simulations for the future climate were two-fold: one was done considering climate
change only, i.e. emissions were kept the same as in present climate simulations, to
assess the contribution of meteorological variables alone on future O 3 concentrations
levels; the other also included future emissions assessing future O 3 concentrations
resulting from both contributions (meteorology and emissions).
To evaluate the risk of Douro vineyard exposure to O 3 the legislated exposure
indicator AOT40 (accumulated concentration of ozone above 40 ppb) was calculated
as an average of AOT40 values for the simulated years, by scenario. The deposition
level results were based on the total O 3 dry deposition accumulated over May to July,
the same period established in the Air Quality Framework Directive 2008/50/CE for
the calculation of the AOT40 indicator. The assessment of the potential damage in
terms of productivity and quality was done through the application of the exposureresponse functions calculated by Soja et al. [5] in their three-year experimental study
on the effects of long-term ozone exposure in grapevines. For the purpose of this
work, the function applied was the one calculated in the last year of the experiment
and thus the one that represents the most damage in vines.
70.3 Modelling Results
A summary of the modelling results is presented in Fig. 70.1, which includes the
results for present climate, and for long-term future climate, considering only the
climate change and considering climate and emissions changes. The delimitated area
in the maps is the DDR.
When considering the climate change impact on O 3 concentration, the modelling
results show an averaged increase of 7% in the AOT40 levels, which is reflected
in a 9 and 7% decrease in productivity and quality. When emission projections are
applied, the AOT40 levels drop approximately 8%, reflecting an increase of 8% in
productivity and 7% in quality. These results indicate that the reduction in AOT40
levels is mostly driven by emissions reduction, which is in agreement with Klingberg
et al. [3] conclusions. Nevertheless, the target value for the protection of vegetation
(18,000 µg m
−3 h) is still exceeded over all the DDR.
When discussing these outcomes it is important to remember that although AOT40
is an important indicator for assessing the risk of vegetation exposure to ozone, it is
known that it has some limitations. For instance, it does not take into consideration
the uptake of ozone by the plants, which depends on the stomatal flux, overestimating
the potential damages. Furthermore, applying Soja et al. [5] functions brings also
uncertainty to the results, since the variety and age of the vines can respond differently
to ozone exposure [6].
Regarding dry O 3 deposition levels, both future simulation scenarios show a
decrease in deposition of almost 50% when compared with the present climate simulations. This indicates that, as opposed to AOT40 levels, the dry deposition is mainly