Component Descriptions

Component 1: Emissions and Exchange Processes

Component 1 (C1) of ÉCLAIRE will improve our process understanding and model representation of the effect of climate change on the emissions of atmospheric direct pollutants (e.g., NH3, NOx) and indirect pollutant pre-cursors (e.g., VOCs for O3 and aerosols) and pollutant dry deposition. This will form the mechanistic basis for deriving more accurate estimates of pollutant inputs and their response to a changing climate (C2) and for developing improved dose/response relationships (C3). 

Overall, Component 1 will deliver:

  • Long-term and campaign-based flux measurements of key components (O3, NO, CO2, NH3, VOCs, aerosol) across a European 9-site network (covering both Nothern and Southern Europe) suitable for process development and model assessment, including the first European network flux measurements for O3 and VOCs (WP1).
  • Improved parameterisations of emissions of NO, NH3 and VOCs in relation to meteorology and pollutant inputs (WP2, WP3).
  • An improved modeling framework for the bi-directional exchange of NO, NO2, O3, VOCs, NH3, aerosols in relation to meteorology, pollutant deposition and plant function, under consideration of in-canopy chemistry (WP1, WP2, WP4).
  • Estimates of Nr and O3 dry and wet deposition at the manipulation sites used in Component 3 (WP4).

Work packages in Component 1:

  • WP1: Field studies on exchange processes
  • WP2: Controlled studies on exchange processes
  • WP3: Modelling emissions processes
  • WP4: Surface exchange modelling

Component 2: Emissions & exchange at local, European to global scales

Component 2 will assimilate the advances in the process understanding of emissions, bi-directional exchange processes and in-canopy reactions from C1, the recent literature and models into spatial chemical transport models to compile modeling frameworks which are mechanistically responsive to changes in climate, land use/land cover and pollutant inputs. The work programme will aim to understand past and predict future trends in Northern Hemispheric O3 concentrations (WP5), and provide frameworks to model spatially and temporally resolved emission fields in response to meteorology (WP6) and pollutant deposition fields both at the European (WP7) and global scale (relevant for WP 5),  and better understand the air quality and climate change interactions at local and regional scales (WP8). These improved modelling systems will be used to provide exposure and deposition inputs for the development of metrics for ecosystem threats (C3) and to assess ecological responses under current and future climate (C4).

Overall, Component 2 will deliver:

  • Improved understanding of past, present and future global, hemispheric and European atmospheric pollution-climate interactions, including the relative pollutant contribution of local source and long-range transport.
  • Quantification of the dynamically varying source contribution of emissions of pollutants and their precursors (i.e., NOx, NH3, BVOC, pyrogenic sources) from ecosystems (natural, semi-natural and agricultural) in response to changing climate, pollutant levels and changing CO2 concentration.
  • Novel maps of pollution metrics across Europe, taking into consideration climate and pollution change, and canopy-chemistry interactions, especially for wet and dry deposition processes.
  • Case studies of local and landscape heterogeneity (input to WP17) and a novel sub-grid parameterization for high-resolution EMEP impacts assessment across Europe.

Work packages in Component 2:

  • WP5: Past and future changes of atmospheric pollutants transported into Europe
  • WP6: Emissions on regional to global scale
  • WP7: Modelling European air pollution and deposition
  • WP8: Assessing local and regional variation

Component 3: Ecological response processes and thresholds

Component 3 will improve our understanding of air pollution impacts on terrestrial ecosystem functioning and services through a combination of data mining and analyses of existing data, and by conducting field scale experiments and process studies on the impacts of air pollution components and their interactions with other important drivers such as climate, land use and land management. These experiments and process studies together with analysis of dose-response relationships will provide new data to develop and improve ecosystem models and threshold setting.

Overall, Component 3 will deliver:

  • A new database and results of meta-analysis on air pollution impacts on land ecosystems including soils.
  • Ecosystem response data on plant responses and ecosystem C balance to experimental changes in air pollution and interacting drivers, including climate and land use differences.
  • Parametrization of the fraction of O3 that is taken up by leaves due to detoxification by constitutive BVOC, under associated environmental constraints and during leaf development, assessment of the relative effects of wet/dry and NOy/NHx deposition and the role of aerosol deposition in exacerbating drought stress.
  • Novel thresholds for key dose-response relationships for application in regional scale modelling and mapping relevant for ecosystem service assessment.
  • Assessments of the effects of combined air pollution and climate change scenarios on ecosystem C/GHG balance, soil quality and vegetation change at the experimental sites, based on integrated models. 

Work packages in Component 3:

  • WP9: Data analyses and data mining
  • WP10: Ecosystem experiments
  • WP11: Novel interactions
  • WP12: Novel thresholds
  • WP13: Ecosystem modelling

Component 4: Ecological responses at regional and European scales

Component 4 of ÉCLAIRE will develop and apply existing process-based models to upscale impacts of air quality, climate change and nutrient availability, and their interactions on plant productivity / C sequestration (WP14) and plant species diversity (WP15) (Figure A), at the continental scale and assess critical loads based on thresholds related to unacceptable impacts on those ecosystem services at this scale (WP16), while accounting for effects of spatial resolution on outputs (WP17).

The approach will advance the compa­tibility of diverse modeling tools, which currently exist for assessing air quality and climate impacts on productivity and/or plant species diversity and soil quality, including DGVMs and DSVMs (Table A). The DGVMs will be further developed and applied in C4 to predict productivity / C sequestration in response to changes in climate, CO2 concentration, N deposition, aerosols/fine particulates (effect of diffuse radiation) and O3 exposure. The DSVMs will be further developed to predict both productivity / carbon sequestration and plant species diversity in response to changes in N and S deposition, climate and soil quality (soil acidity, phosphate and base cation availability), while adding effects of CO2 and O3 exposure. The DSVMs will also be used to derive European maps of novel thresholds for N and S deposition and O3 exposure for protecting plant ecosystems and their exceedances (WP16). These maps will be based on approaches developed under WP11. Apart from impacts at the European scale, the DSVMs will finally be applied at fine-scale resolution to gain insight in uncertainties due to aggregation of high resolution estimates to the lower resolution in Europe-wide assessments (WP17). The innovation lies especially in cross-community collaboration to make integrated assessments possible and integrate aspects. The ensemble approach to the modelling (Table A) will enable us to identify the most successful model formulations and levels of complexity required to describe each process (based on site-scale testing in C3 and regional testing in C4) and will provide an estimation of prediction uncertainty associated with different model structures (linked with Task 21.3). This is often ignored in uncertainty assessments that only account for parameter uncertainty.

By drawing together large-scale models and datasets, this component will allow ÉCLAIRE to provide a Europe-wide assessment of air pollution impacts under changing climate conditions in terms of plant pro­duc­tivity, plant community composition and plant/soil C sequestration. We will use the same models for simulating atmospheric and climate change impacts on productivity / C sequestration and GHG exchange in WP14 and for impacts on plant species diversity and soil and water quality in WP15. The last task holds for the SVGMs, since these models focus also on plant species diversity. The parallel improvement and application of SVGMs and DGVMs, linking specific experimental and monitoring studies in C3 (WP9 and WP10) with development, testing and application of models at larger scales in C4 (WP14 and WP15) will allow major advances in understanding, challenging the assumptions of the traditionally separate research communities (Figure B).

Figure A: Relationships that will be investigated between air quality and climate impacts on productivity (carbon and greenhouse gas emissions), soil quality and plant species community composition.

air quality climate change relationship

Figure B: Role of DGVMs (LPJ, JULES, CLM) and SVGMs (VSD+, FORSPACE, ROMUL, EUMOVE) to assess air quality and climate impacts on productivity plant communities and soil quality at European scale (C4) and validate results on data (C3)

role of DGVMs

Table 1.1: Summary of numerical models used in ÉCLAIRE.

Model type





Dynamic vegetation & trace gas emissions models (DGVMs)

Regional, Europe to globe,

Dynamic response of vegetation and soil to climate and CO2 drivers, in some cases also to N-deposition and ozone levels. May be applied to potential natural vegetation or include crop cover and processes

Dynamically varying biogenic emissions (e.g., NOx, BVOC, fire). Response of vegetation  and soil C- and N- pools and cycles, to changing climate, atmospheric composition and in some cases N or O3


Soil process and trace gas emission models (DSVMs)

Point to Europe (2-D)

Soil C-N decomposition processes and nutrient chemistry. Relies on prescribed soil and vegetation properties, may be applied to natural or agricultural ecosystems

Response of soil C and N pools, trace gas emissions, nutrient levels to changes in emissions, climate, vegetation litter input or management


Deposition /
bi-directional exchange models

Point /

1-D column

Within-and above canopy exchange (O3, VOC, NOx, aerosol) and in-canopy chemistry

O3 stomata deposition-dose effects; Nr deposition; pollutant life-time

CanT, DO3SE, various CTM sub-models

Regional Climate model (RCMs)


Calculates meteorology for future climate simulations, downscaling from large-scale GCM results to 50 km  over Europe

Provides future climate meteorology for DVGM, DSVMS and CTMs, as well as future climate data


Chemistry transport model (CTMs)

Regional, Europe to globe,


Atmospheric reaction pathways, transport and deposition of natural and anthropogenic emissions, in some cases also in response to climate change

Variable O3 & other gases or aerosol,, wet/dry deposition of O3, N and other compounds; PODY (phytotoxic ozone dose)


Biodiversity assessment model



Species composition response to changing soil properties (e.g., %C, %N, soil chemistry) or Ellenberg ecosystem indicators

Biodiversity indicators based on species prevalence


Integrated assessment model

Countries regions

Transfer coefficients, emission factors, optimisation targets, costs, etc

Optimised emissions and costs, translated into transfer matrix linked with CTM



Overall, Component 4 will deliver:

  • Updated versions of the DGVMs LPJ-Guess, JULES, LCM-CN and ORCHIDEE that predict the interacting effects of O3 exposure, N deposition/ N availability, CO2 fertilization, particulate matter and climate change on productivity / carbon sequestration.
  • Updated version of DSVMs VSD+- FORSPACE and MADOC-JULES linked to a EUMOVE to predict impacts of drivers on abiotic soil conditions and plant species diversity.
  • Predictions of carbon sequestration and plant species diversity at European scale in response to various ÉCLAIRE scenarios of future emissions and climate change using a range of DGVMs and DSVMs, illustrating the uncertainty in predictions in view of uncertainties in representing processes in the models.
  • European maps of novel thresholds for NOx deposition, NH3 deposition and O3 exposure and their exceedance, with the spatial uncertainties illustrated by application of high resolution estimates in case-study areas.

Work packages in Component 4:

  • WP14: Air pollution-climate impacts on European C stocks and greenhouse gas emissions  
  • WP15: Interactive air pollution-climate impacts on biodiversity and soil quality
  • WP16: European maps of novel thresholds & exceedances
  • WP17: Local variation in threshold exceedance

Component 5: Integrated risk assessment and policy tools

In order to meet the aims of ÉCLAIRE and to provide ÉCLAIRE output relevant for European environmental policy, considerable additions to the current approaches are needed. This starts from the valuation of economic damage. Despite the considerable difficulties involved, an extension of benefit estimation to include ecosystems damage (based on the costs of ecosystems services) will be performed. Next, the economic basis (and the measures for emission abatement) needs to be extended further into the future. The available toolset (currently limited to 2030) will be extended to 2050, with a scoping assessment beyond 2050 (target year: 2100). Finally, also the underlying CTM will be parameterized to cover future conditions under climate change and to include new indicators as developed elsewhere in ÉCLAIRE (C3 and C4).

ÉCLAIRE will use the GAINS model to assess the effects of air pollution on ecosystems. Impacts and novel thresholds will be integrated either directly into the GAINS model code or by external analysis. Costs of abatement measures will be determined and compared with the value of ecosystems service maintained against pollution damage. Valuation will use a marginal approach to the extent possible.

In contrast to previous assessments, modelling will explicitly refer to conditions of climate change, i.e. altered meteorological conditions that may also affect species composition and an altered ecosystem’s response to air pollution, all implemented in revised source-receptor matrices. The benefits will include the ecosystem services, but also the relation to climate change effects where air pollution or changes in the atmosphere-biosphere interaction will play a role.

Delivering central results from ÉCLAIRE, the work will require information from C2, regarding source-receptor matrices, and C3 and C4, for ecosystems effects. At the same time, outputs from the PEGASOS project on effects of climate on health based air chemistry interactions can be integrated.

Overall, Component 5 will deliver:

  • Description of data for quantifying and valuating ecosystem effects
  • Implementation of new effect indicators and critical thresholds in the GAINS modelling system
  • Cost optimization of emission abatement and cost-benefit analysis of pollution abatement
  • Policy recommendations regarding ecosystem protection under conditions of climate change

Work packages in Component 5:

  • WP18: Deriving economic impacts and valuation of ecosystem services 
  • WP19: Integrating air pollution effects under climate change
  • WP20: Implications for mitigation & adaptation strategies
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