Michal Belda

On the long-term impact of emissions from central European cities on regional air quality

For the purpose of qualifying and quantifying the impact of urban emission from Central European cities on the present-day regional air-quality, the regional climate model RegCM4.2 was coupled with the chemistry transport model CAMx, including two-way interactions. A series of simula5 tions was carried out for the 2001–2010 period either with all urban emissions included (base case) or without considering urban emissions. Further, the sensitivity of ozone production to urban emissions was examined by performing reduction experiments with −20 % emission perturbation of NOx 10 and/or non-methane volatile organic compounds (NMVOC). The modeling system’s air-quality related outputs were evaluated using AirBase and EMEP surface measurements showed reasonable reproduction of the monthly variation for ozone (O3), but the annual cycle of nitrogen dioxide (NO2) 15 and sulfur dioxide (SO2) is more biased. In terms of hourly correlations, values achieved for ozone and NO2 are 0.5–0.8 and 0.4–0.6, but SO2 is poorly or not correlated at all with measurements (r around 0.2–0.5). The modeled fine particulates (PM2.5) are usually underestimated, especially in win20 ter, mainly due to underestimation of nitrates and carbonaceous aerosols. European air-quality measures were chosen as metrics describing the cities emission impact on regional air pollution. Due to urban emissions, significant ozone titration oc25 curs over cities while over rural areas remote from cities, ozone production is modeled, mainly in terms of number of exceedances and accumulated exceedances over the threshold of 40 ppbv. Urban NOx, SO2 and PM2.5 emissions also significantly contribute to concentrations in the cities them30 selves (up to 50–70 % for NOx and SO2, and up to 60 % for PM2.5), but the contribution is large over rural areas as well (10–20 %). Although air pollution over cities is largely determined by the local urban emissions, considerable (often a few tens of %) fraction of the concentration is attributable 35 to other sources from rural areas and minor cities. For the case of Prague (Czech Republic capital), it is further shown that the inter-urban interference between large cities does not play an important role which means that the impact on a chosen city of emissions from all other large cities is very small. 40 At last, is shown that to achieve significant ozone reduction over cities in central Europe, the emission control strategies have to focus on the reduction of NMVOC, as reducing NOx (due to suppressed titration) leads often to increased O3. The influence over rural areas is however always in favor of im45 proved air-quality, i.e. both NOx and/or NMVOC reduction ends up in decreased ozone pollution, mainly in terms of exceedances.

CECILIA Regional Climate Simulations for Future Climate: Analysis of Climate Change Signal

Regional climate models (RCMs) are important tools used for downscaling climate simulations from global scale models. In project CECILIA, two RCMs were used to provide climate change information for regions of Central and Eastern Europe. Models RegCM and ALADIN-Climate were employed in downscaling global simulations from ECHAM5 and ARPEGE-CLIMAT under IPCC A1B emission scenario in periods 2021–2050 and 2071–2100. Climate change signal present in these simulations is consistent with respective driving data, showing similar large-scale features: warming between 0 and 3°C in the first period and 2 and 5°C in the second period with the least warming in northwestern part of the domain increasing in the southeastern direction and small precipitation changes within range of

Forecasting Models for Urban Warming in Climate Change

Defining UHI phenomenon required and interdisciplinar approach using both simulation models and climate data elaborations at regional and metropolitan level. In particular the WP 3 of UHI project provided a detailed survey on the main studies and practices to counteract urban heat islands in different European areas; discussed climate models at regional level; simulated the evaluation of urban warming in the different cities involved in the project, providing locally proper measuring and analysis in connection with the specific urban forms.

High resolution modelling of anthropogenic heat from traffic in urban canopy: A sensitivity study

Impact of climate change is often amplified in urban areas - particularly during the heat waves, the extreme temperatures are even more pronounced in cities due to the effect urban heat island (UHI). It is therefore important to improve our understanding of heat fluxes and energy balance in urbanized areas. We investigate the possibility of high resolution urban canopy modelling using PALM model. To account for the realistic implementation of urban canopy processes in complex urban geometry we enhanced PALM model including some of the most important urban canopy mechanisms including detailed description of physical properties of urban surfaces, calculation of shape view factors and plant canopy sink factor to model accurately both shortwave and longwave radiation budgets, and heat transfer within urban surfaces and on the interfaces of surfaces and atmosphere or ground. Such approach allows for very detailed modelling in high spatial and temporal scale. The simulation of the impact of anthropogenic heat from transportation has been conducted as one of the pilot experiments to test feasibility of this approach and also sensitivity of highly unstable turbulent flow heat exchange to a relatively small perturbation of input parameters.

Urban Impact on Air Quality in RegCM/CAMx Couple for MEGAPOLI Climate Change Study in High Resolution

For the purpose of qualifying and quantifying the climate forcing due to atmospheric chemistry/aerosols on regional scale, the regional climate model RegCM3 has been coupled with the chemistry/aerosol model CAMx. Experiments with the couple have been run for EC FP7 project MEGAPOLI assessing the impact of the megacities and industrialized areas on climate. New domain have been settled in 10 km resolution including all the European “megacities” regions, i.e. London metropolitan area, Paris region, industrialized Ruhr area, Po valley etc. TNO emissions are adopted to resolve urban areas. A sensitivity test of the resolution effect is presented to reveal whether the concept of effective emission indices could help to parameterize the urban plume effects in lower resolution models. The sensitivity test to switch on/off Paris area emissions is analysed as well.

On the Comparison of Nesting of Lagrangian Air-Pollution Model Smog to Numerical Weather Prediction Model ETA and Eulerian CTM CAMX to NWP Model MM5: Ozone Episode Simulation

711 The spatial distribution of air pollution on the local scale of parts of the territory in Czech Republic is simulated by means of Charles University Lagrangian puff model SMOG nested in NWP model ETA. The results are used for the assessment of the concentration fields of ozone, nitrogen oxides and other ozone precursors. A current improved version of the model based on Bednar et al. (2001) covers up to 18 groups of basic compounds and it is based on trajectory computation and puff interaction both by means of Gaussian diffusion, mixing and chemical reactions of basic species. Results of summer photochemical smog episode simulations are compared to results obtained by another couple adopted in the framework of the national project as a basis for further development of data assimilation techniques, Eulerian CTM CAMx nested in NWP model MM5. There are measured data from field campaigns for some episodes as well as air-quality monitoring station data available for comparison of model results with reality. Usually, there is a problem with emission data for the simulations and definitely they are far from actual instantaneous data. Both the couples have rather older databases of emissions available with many uncertainities, for

Verification of Ship Plumes Modelling and Their Impacts on Air Quality and Climate Change in QUANTIFY EC 6FP Project

The impact of emission from transportation on climate change is being quantified in EC FP6 Integrated Project QUANTIFY. In Activity 2 the analysis of the dilution and transformation of the emission from microscale at exhausts and plumes till mesoscale distribution will be provided from all modes of transportation. In this contribution the mesoscale simulations of ship emission impact on atomspheric pollution are studied with emphasis to compare the simulation with reality analyzed by means of flight measurement during the field campaign. In framework of the project the modeling studies are supposed to support the field campaign as well. The sensitivity of the impact on air quality and composition is analyzed as well with respect to ship emissions.

Regional Climate Change Impacts on Air Quality in CECILIA EC 6FP Project

Recent studies show considerable effect of atmospheric chemistry and aerosols on climate on regional and local scale. For the purpose of qualifying and quantifying the magnitude of climate forcing due to atmospheric chemistry/aerosols on regional scale, the development of coupling of regional climate model and chemistry/aerosol model has been started recently on the Department of Meteorology and Environmental Protection, Faculty of Mathematics and Physics, Charles University in Prague, for the EC 6FP Project QUANTIFY and finally for EC 6FP Project CECILIA. One of the project objectives, aiming to study climate change impacts in Central and Eastern Europe based on very high resolution simulations using regional climate models (RCM) in 10 km grid, is dealing with climate change impacts on and interaction to air quality. For this coupling, existing regional climate model and chemistry transport model are used. Climate is calculated using model RegCM and ALADIN-Climate while chemistry is solved by model CAMx. Climate change impacts on large urban and industrial areas modulated by topographical and land-use effects which can be resolved at the 10 km scale, are investigated by CECILIA as well. Meteorological fields generated by RCM drive CAMx transport, chemistry and a dry/wet deposition. A preprocessor utility was developed for transforming RegCM provided fields to CAMx input fields and format. As the first step, the distribution of pollutants can be simulated off-line for long period in the model couple. There is critical issue of the emission inventories available both for present and scenarios runs as well as cross-boundary transport for regional simulations. The next step is the inclusion of the radiative active agents from CAMx into RCM radiative transfer scheme to calculate the changes of heating rates. Only the modification of radiative transfer due to atmospheric chemistry/aerosols is taken into account first, the indirect effect of aerosols will be studied later. Ten years time slices for present, control and scenarios runs for mid- and end of century are supposed in framework of the project. Some sensitivity runs will be run in present climate.