Freeze Out Process with In-Medium Nucleon Mass

We investigate the kinetic freeze out scenario of a nucleon gas through a finite layer. The in-medium mass modification of nucleons and it's impact on the freeze out process is studied. A considerable modification of the thermodynamical parameters temperature, flow-velocity, energy density and particle density has been found in comparison with evaluations which use a constant vacuum nucleon mass.Comment: 6 pages, 4 figures, Proceeding of the Conference "Quark Matter 2005", 4th - 9th August 2005, Budapest/Hungar

The impact of meteorological forcings on gas phase air pollutants over Europe

International audienc

Impact of emissions and +2 °C climate change upon future ozone and nitrogen dioxide over Europe

International audienc

Impacts of regional climate change on air quality projections and associated uncertainties

International audienc

Particulate matter air pollution in Europe in a +2 °C warming world

International audienc

Performance of European chemistry transport models as function of horizontal resolution

Air pollution causes adverse effects on human health as well as ecosystems and crop yield and also has an impact on climate change trough short-lived climate forcers. To design mitigation strategies for air pollution, 3D Chemistry Transport Models (CTMs) have been developed to support the decision process. Increases in model resolution may provide more accurate and detailed information, but will cubically increase computational costs and pose additional challenges concerning high resolution input data. The motivation for the present study was therefore to explore the impact of using finer horizontal grid resolution for policy support applications of the European Monitoring and Evaluation Programme (EMEP) model within the Long Range Transboundary Air Pollution (LRTAP) convention. The goal was to determine the "optimum resolution" at which additional computational efforts do not provide increased model performance using presently available input data. Five regional CTMs performed four runs for 2009 over Europe at different horizontal resolutions. The models' responses to an increase in resolution are broadly consistent for all models. The largest response was found for NO2 followed by PM10 and O3. Model resolution does not impact model performance for rural background conditions. However, increasing model resolution improves the model performance at stations in and near large conglomerations. The statistical evaluation showed that the increased resolution better reproduces the spatial gradients in pollution regimes, but does not help to improve significantly the model performance for reproducing observed temporal variability. This study clearly shows that increasing model resolution is advantageous, and that leaving a resolution of 50 km in favour of a resolution between 10 and 20 km is practical and worthwhile. As about 70% of the model response to grid resolution is determined by the difference in the spatial emission distribution, improved emission allocation procedures at high spatial and temporal resolution are a crucial factor for further model resolution improvements.JRC.H.2-Air and Climat

POMI: A Model Intercomparison exercise over the Po valley

A collaborative research project for air pollution reduction was set up in 2006 between the Joint Research Centre of the European Commission (JRC) and the Authorities of the Lombardy Region in Italy. Among other research activities the PO valley Model Intercomparison exercise (POMI) has been carried out in order to explore the changes in air-quality in response to changes in emissions. The starting point was the evaluation of the simulated particulate matter and ozone against observations for the year 2005 of the six participating Chemical Transport Models’ (CTM). As models were run with the same configuration in terms of spatial resolution, boundary condition, emissions and meteorology, the differences presented in the models’ results should only be related to their formulation. As described in the paper much effort has been put to improve the accuracy of emissions and meteorology. Nevertheless none of the models using the proposed meteorology succeeded to fulfill the performance criteria set in the 2008 Air Quality Directive and in the literature for particulate matter, while also for ozone the results are not very satisfying. Possible explanations for this common behavior and a discussion of the differences among models’ results are presented.JRC.H.2-Air and Climat