Learn More
A model has been developed to estimate stomatal ozone flux across Europe for a number of important species. An initial application of this model is illustrated for two species, wheat and beech. The model calculates ozone flux using European Monitoring and Evaluation Programme (EMEP) model ozone concentrations in combination with estimates of the(More)
Two very different types of approaches are currently in use today for indicating risk of ozone damage to vegetation in Europe. One approach is the so-called AOTX (accumulated exposure over threshold of Xppb) index, which is based upon ozone concentrations only. The second type of approach entails an estimate of the amount of ozone entering via the stomates(More)
Forests in Europe face significant changes in climate, which in interaction with air quality changes, may significantly affect forest productivity, stand composition and carbon sequestration in both vegetation and soils. Identified knowledge gaps and research needs include: (i) interaction between changes in air quality (trace gas concentrations), climate(More)
Continuous and area-integrating monitoring of methane (CH4) and carbon dioxide (CO2) emissions was performed for 6 and 9 months, respectively, at a municipal landfill in Finland with the micrometeorological eddy covariance (EC) method. The mean CH4 emission from June to December was 0.53 mg m(-2) s(-1), while the CO2 emission between February and December(More)
The first measurements of nitrous oxide (N20) emissions from a landfill by the eddy covariance method are reported. These measurements were compared to enclosure emission measurements conducted at the same site. The average emissions from the municipal landfill of the Helsinki Metropolitan Area were 2.7 mg N m(-2) h(-1) and 6.0 mg N m(-2) h(-1) measured(More)
Monitoring and modelling of deposition of air pollutants is essential to develop and evaluate policies to abate the effects related to air pollution and to determine the losses of pollutants from the atmosphere. Techniques for monitoring wet deposition fluxes are widely applied. A recent intercomparison experiment, however, showed that the uncertainty in(More)
A discussion is presented on the application of micrometeorological deposition modelling principles to improve the characterisation of vegetation exposure to ozone and thus the use of critical levels as the basis of targeted emission control. The AOT40 (accumulated exposure over a threshold of 40 ppb or nl l(-1)) ozone exposure index is shown to impose a(More)
A statistical model for estimating AOT40 from time-integrated concentration data is presented and validated. AOT40 is a numerical index that describes the ozone exposure of ecosystems in terms of the hourly accumulated exposure over a threshold of 40 ppb. A rather simple model formulation was achieved by approximating the frequency distribution of hourly(More)
This study evaluates the robustness of the AOTX and AF(st)Y indices for assessing the ozone-induced risk to vegetation. These indices represent the accumulated concentration and stomatal flux, respectively, above a threshold value. The robustness is expressed as the sensitivity to changes in inputs and the uncertainty due to input errors. The input data are(More)
Significant climate risks are associated with a positive carbon-temperature feedback in northern latitude carbon-rich ecosystems, making an accurate analysis of human impacts on the net greenhouse gas balance of wetlands a priority. Here, we provide a coherent assessment of the climate footprint of a network of wetland sites based on simultaneous and(More)