22 results on '"Halenka, Tomas"'
Search Results
2. Project FOCI - Non-CO2 forcers and their climate, weather, air quality and health impacts
- Author
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Halenka, Tomas and Sokhi, Ranjeet S.
- Abstract
While overall global warming with the causes and global processes connected to well-mixed CO2, and its impacts on global to continental scales are well understood with a high level of confidence, there are knowledge gaps concerning the impact of many other non-CO2radiative forcers leading to low confidence in the conclusions. This relates mainly to specific anthropogenic and natural precursor emissions of short-lived GHGs and aerosols and their precursors. These gaps and uncertainties also exist in their subsequent effects on atmospheric chemistry and climate, through direct emissions dependent on changes in e.g., agriculture production and technologies based on scenarios for future development as well as feedbacks of global warming on emissions, e.g., permafrost thaw. The main goal of the EC Horizon Europe project FOCI, is to assess the impact of key radiative forcers, where and how they arise, the processes of their impact on the climate system, to find and test an efficient implementation of these processes into global Earth System Models and into Regional Climate Models, eventually coupled with CTMs, and finally to use the tools developed to investigate mitigation and/or adaptation policies incorporated in selected scenarios of future development targeted at Europe and other regions of the world. We will develop new regionally tuned scenarios based on improved emissions to assess the effects of non-CO2 forcers. Mutual interactions of the results and climate services producers and other end-users will provide feedbacks for the specific scenarios preparation and potential application to support the decision making, including climate policy., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)
- Published
- 2023
3. Global warming-induced changes in climate zones based on CMIP5 projections
- Author
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Belda, Michal, Holtanová, Eva, Kalvová, Jaroslava, and Halenka, Tomáš
- Published
- 2016
4. Evaluation of CMIP5 present climate simulations using the Köppen-Trewartha climate classification
- Author
-
Belda, Michal, Holtanová, Eva, Halenka, Tomáš, Kalvová, Jaroslava, and Hlávka, Zdeněk
- Published
- 2015
5. Climate classification revisited : from Köppen to Trewartha
- Author
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Belda, Michal, Holtanová, Eva, Halenka, Tomáš, and Kalvová, Jaroslava
- Published
- 2014
6. CECILIA regional climate simulations for the present climate : validation and inter-comparison
- Author
-
Skalák, Petr, Déqué, Michel, Belda, Michal, Farda, Aleš, Halenka, Tomáš, Csima, Gabriella, Bartholy, Judit, Caian, Mihaela, and Spiridonov, Valery
- Published
- 2014
7. Advances in air quality research – current and emerging challenges
- Author
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Sokhi, Ranjeet S., Moussiopoulos, Nicolas, Baklanov, Alexander, Bartzis, John, Coll, Isabelle, Finardi, Sandro, Friedrich, Rainer, Geels, Camilla, Grönholm, Tiia, Halenka, Tomas, Ketzel, Matthias, Maragkidou, Androniki, Matthias, Volker, Moldanova, Jana, Ntziachristos, Leonidas, Schäfer, Klaus, Suppan, Peter, Tsegas, George, Carmichael, Greg, Franco, Vicente, Hanna, Steve, Jalkanen, Jukka-Pekka, Velders, Guus J. M., Kukkonen, Jaakko, Ilmatieteen laitos, and Finnish Meteorological Institute
- Subjects
air pollution ,forecasting ,air quality - Abstract
This review provides a community’s perspective on air quality research focusing mainly on developments over the past decade. The article provides perspectives on current and future challenges as well as research needs for selected key topics. While this paper is not an exhaustive review of all research areas in the field of air quality, we have selected key topics that we feel are important from air quality research and policy perspectives. After providing a short historical overview, this review focuses on improvements in characterizing sources and emissions of air pollution, new air quality observations and instrumentation, advances in air quality prediction and forecasting, understanding interactions of air quality with meteorology and climate, exposure and health assessment, and air quality management and policy. In conducting the review, specific objectives were (i) to address current developments that push the boundaries of air quality research forward, (ii) to highlight the emerging prominent gaps of knowledge in air quality research, and (iii) to make recommendations to guide the direction for future research within the wider community. This review also identifies areas of particular importance for air quality policy. The original concept of this review was borne at the International Conference on Air Quality 2020 (held online due to the COVID 19 restrictions during 18–26 May 2020), but the article incorporates a wider landscape of research literature within the field of air quality science. On air pollution emissions the review highlights, in particular, the need to reduce uncertainties in emissions from diffuse sources, particulate matter chemical components, shipping emissions, and the importance of considering both indoor and outdoor sources. There is a growing need to have integrated air pollution and related observations from both ground-based and remote sensing instruments, including in particular those on satellites. The research should also capitalize on the growing area of low-cost sensors, while ensuring a quality of the measurements which are regulated by guidelines. Connecting various physical scales in air quality modelling is still a continual issue, with cities being affected by air pollution gradients at local scales and by long-range transport. At the same time, one should allow for the impacts from climate change on a longer timescale. Earth system modelling offers considerable potential by providing a consistent framework for treating scales and processes, especially where there are significant feedbacks, such as those related to aerosols, chemistry, and meteorology. Assessment of exposure to air pollution should consider the impacts of both indoor and outdoor emissions, as well as application of more sophisticated, dynamic modelling approaches to predict concentrations of air pollutants in both environments. With particulate matter being one of the most important pollutants for health, research is indicating the urgent need to understand, in particular, the role of particle number and chemical components in terms of health impact, which in turn requires improved emission inventories and models for predicting high-resolution distributions of these metrics over cities. The review also examines how air pollution management needs to adapt to the abovementioned new challenges and briefly considers the implications from the COVID-19 pandemic for air quality. Finally, we provide recommendations for air quality research and support for policy.
- Published
- 2022
8. Modelling the effects of climate change on air quality over Central and Eastern Europe : concept, evaluation and projections
- Author
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Juda-Rezler, Katarzyna, Reizer, Magdalena, Huszar, Peter, Krüger, Bernd C., Zanis, Prodromos, Syrakov, Dimiter, Katragkou, Eleni, Trapp, Wojciech, Melas, Dimitris, Chervenkov, Hristo, Tegoulias, Ioannis, and Halenka, Tomas
- Published
- 2012
9. Land–atmosphere interactions in sub-polar and alpine climates in the CORDEX flagship pilot study Land Use and Climate Across Scales (LUCAS) models – Part 1: Evaluation of the snow-albedo effect.
- Author
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Daloz, Anne Sophie, Schwingshackl, Clemens, Mooney, Priscilla, Strada, Susanna, Rechid, Diana, Davin, Edouard L., Katragkou, Eleni, de Noblet-Ducoudré, Nathalie, Belda, Michal, Halenka, Tomas, Breil, Marcus, Cardoso, Rita M., Hoffmann, Peter, Lima, Daniela C. A., Meier, Ronny, Soares, Pedro M. M., Sofiadis, Giannis, Strandberg, Gustav, Toelle, Merja H., and Lund, Marianne T.
- Subjects
LAND-atmosphere interactions ,SNOW cover ,ATMOSPHERIC models ,LAND use ,RADIATIVE forcing ,ABLATION (Glaciology) ,CLIMATE sensitivity - Abstract
Seasonal snow cover plays a major role in the climate system of the Northern Hemisphere via its effect on land surface albedo and fluxes. In climate models the parameterization of interactions between snow and atmosphere remains a source of uncertainty and biases in the representation of local and global climate. Here, we evaluate the ability of an ensemble of regional climate models (RCMs) coupled with different land surface models to simulate snow–atmosphere interactions over Europe in winter and spring. We use a previously defined index, the snow-albedo sensitivity index (SASI), to quantify the radiative forcing associated with snow cover anomalies. By comparing RCM-derived SASI values with SASI calculated from reanalyses and satellite retrievals, we show that an accurate simulation of snow cover is essential for correctly reproducing the observed forcing over middle and high latitudes in Europe. The choice of parameterizations, and primarily the choice of the land surface model, strongly influences the representation of SASI as it affects the ability of climate models to simulate snow cover accurately. The degree of agreement between the datasets differs between the accumulation and ablation periods, with the latter one presenting the greatest challenge for the RCMs. Given the dominant role of land surface processes in the simulation of snow cover during the ablation period, the results suggest that, during this time period, the choice of the land surface model is more critical for the representation of SASI than the atmospheric model. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. Advances in Air Quality Research - Current and Emerging Challenges.
- Author
-
Sokhi, Ranjeet S, Moussiopoulos, Nicolas, Baklanov, Alexander, Bartzis, John, Coll, Isabelle, Finardi, Sandro, Friedrich, Rainer, Geels, Camilla, Gronholm, Tiia, Halenka, Tomas, Ketzel, Matthias, Maragkidou, Androniki, Matthias, Volker, Moldanova, Jana, Ntziachristos, Leonidas, Schafer, Klaus, Suppan, Peter, Tsegas, George, Carmichael, Greg, and Franco, Vicente
- Abstract
This review provides a community's perspective on air quality research focussing mainly on developments over the past decade. The article provides perspectives on current and future challenges as well as research needs for selected key topics. While this paper is not an exhaustive review of all research areas in the field of air quality, we have selected key topics that we feel are important from air quality research and policy perspectives. After providing a short historical overview, this review focuses on improvements in characterising sources and emissions of air pollution, new air quality observations and instrumentation, advances in air quality prediction and forecasting, understanding interactions of air quality with meteorology and climate, exposure and health assessment, and air quality management and policy. In conducting the review, specific objectives were (i) to address current developments that push the boundaries of air quality research forward, (ii) to highlight the emerging prominent gaps of knowledge in air quality research and (iii) and to make recommendations to guide the direction for future research within the wider community. This review also identifies areas of particular importance for air quality policy. The original concept of this review was borne at the International Conference on Air Quality 2020 (held online due to the COVID 19 restrictions during 18-26 May 2020), but the article incorporates a wider landscape of research literature within the field of air quality science. On air pollution emissions the review highlights, in particular, the need to reduce uncertainties in emissions from diffuse sources, particulate matter chemical components, shipping emissions and the importance of considering both indoor and outdoor sources. There is a growing need to have integrated air pollution and related observations from both ground based and remote sensing instruments, including especially those on satellites. The research should also capitalize on the growing area of lower cost sensors, while ensuring a quality of the measurements which are regulated by guidelines. Connecting various physical scales in air quality modelling is still a continual issue, with cities being affected by air pollution gradients at local scales and by long range transport. At the same time, one should allow for the impacts from climate change on a longer timescale. Earth system modelling offers considerable potential by providing a consistent framework for treating scales and processes, especially where there are significant feedbacks, such as those related to aerosols, chemistry and meteorology. Assessment of exposure to air pollution should consider both the impacts of indoor and outdoor emissions, as well as application of more sophisticated, dynamic modelling approaches to predict concentrations of air pollutants in both environments. With particulate matter being one of the most important pollutants for health, research is indicating the urgent need to understand, in particular, the role of particle number and chemical components in terms of health impact, which in turn requires improved emission inventories and models for predicting high resolution distributions of these metrics over cities. The review also examines, how air pollution management needs to adapt to the above-mentioned new challenges and briefly considers the implications from the COVID-19 pandemic for air quality. Finally, we provide recommendations for air quality research and support for policy. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
11. Impact of urban canopy meteorological forcing on aerosol concentrations.
- Author
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Huszar, Peter, Belda, Michal, Karlický, Jan, Bardachova, Tatsiana, Halenka, Tomas, and Pisoft, Petr
- Subjects
CLIMATOLOGY ,METEOROLOGY ,ATMOSPHERIC aerosols ,WIND speed ,TURBULENT diffusion (Meteorology) ,TEMPERATURE ,NITRATES - Abstract
²The regional climate model RegCM4 extended with the land surface model CLM4.5 was coupled to the chemistry transport model CAMx to analyze the impact of urban meteorological forcing on surface fine aerosol (PM
2.5 ) concentrations for summer conditions over the 2001-2005 period, focusing on the area of Europe. Starting with the analysis of the meteorological modifications caused by urban canopy forcing, we found a significant increase in urban surface temperatures (up to 2-3 K), a decrease of specific humidity (by up to 0.4-0.6 gkg-1 ), a reduction of wind speed (up to -1 ms-1 ) and an enhancement of vertical turbulent diffusion coefficient (up to 60-70 m²s-1 ). These modifications translated into significant changes in surface aerosol concentrations that were calculated by a "cascading" experimental approach. First, none of the urban meteorological effects were considered. Then, the temperature effect was added, then the humidity and the wind, and fi- nally, the enhanced turbulence was considered in the chemical runs. This facilitated the understanding of the underlying processes acting to modify urban aerosol concentrations. Moreover, we looked at the impact of the individual aerosol components as well. The urbanization-induced temperature changes resulted in a decrease of PM2.5 by -1.5 yo -2 µgm-3 , while decreased urban winds resulted in increases by -2 µgm-3 . The enhanced turbulence over urban areas resulted in decreases of PM2.5 by -1.5 yo -2 µgm-3 . The combined effect of all individual impact depends on the competition between the partial impacts and can reach up to -3 µgm-3 for some cities, especially when the temperature impact was stronger in magnitude than the wind impact. The effect of changed humidity was found to be minor. The main contributor to the temperature impact is the modification of secondary inorganic aerosols, mainly nitrates, while the wind and turbulence impact is most pronounced in the case of primary aerosol (primary black and organic carbon and other fine particle matter). The overall as well as individual impacts on secondary organic aerosol are very small, with the increased turbulence acting as the main driver. The analysis of the vertical extent of the aerosol changes showed that the perturbations caused by urban canopy forcing, besides being large near the surface, have a secondary maximum for turbulence and wind impact over higher model levels, which is attributed to the vertical extent of the changes in turbulence over urban areas. The validation of model data with measurements showed good agreement, and we could detect a clear model improvement in some areas when including the urban canopy meteorological effects in our chemistry simulations. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
12. Forecasting Models for Urban Warming in Climate Change.
- Author
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Fallmann, Joachim, Emeis, Stefan, Wagner, Sven, Ketterer, Christine, Matzarakis, Andreas, Krüzselyi, Ilona, Zsebeházi, Gabriella, Kovács, Mária, Halenka, Tomas, Huszár, Peter, Belda, Michal, Tomozeiu, Rodica, and Botarelli, Lucio
- Published
- 2016
- Full Text
- View/download PDF
13. Urban Impact on Air Quality in RegCM/CAMx Couple for MEGAPOLI Climate Change Study in High Resolution.
- Author
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Halenka, Tomas, Huszar, Peter, and Belda, Michal
- Published
- 2012
- Full Text
- View/download PDF
14. Regional Climate Change Impacts on Air Quality in CECILIA EC 6FP Project.
- Author
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Halenka, Tomas, Huszar, Peter, and Belda, Michal
- Abstract
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. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
15. Transport impacts on atmosphere and climate: Land transport
- Author
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Uherek, Elmar, Halenka, Tomas, Borken-Kleefeld, Jens, Balkanski, Yves, Berntsen, Terje, Borrego, Carlos, Gauss, Michael, Hoor, Peter, Juda-Rezler, Katarzyna, Lelieveld, Jos, Melas, Dimitrios, Rypdal, Kristin, and Schmid, Stephan
- Subjects
- *
TRANSPORTATION & the environment , *CLIMATE change , *ATMOSPHERE , *AIR pollution , *EMISSIONS (Air pollution) , *GLOBAL warming , *HALOCARBONS , *EMISSION control - Abstract
Abstract: Emissions from land transport, and from road transport in particular, have significant impacts on the atmosphere and on climate change. This assessment gives an overview of past, present and future emissions from land transport, of their impacts on the atmospheric composition and air quality, on human health and climate change and on options for mitigation. In the past vehicle exhaust emission control has successfully reduced emissions of nitrogen oxides, carbon monoxide, volatile organic compounds and particulate matter. This contributed to improved air quality and reduced health impacts in industrialised countries. In developing countries however, pollutant emissions have been growing strongly, adversely affecting many populations. In addition, ozone and particulate matter change the radiative balance and hence contribute to global warming on shorter time scales. Latest knowledge on the magnitude of land transport''s impact on global warming is reviewed here. In the future, road transport''s emissions of these pollutants are expected to stagnate and then decrease globally. This will then help to improve the air quality notably in developing countries. On the contrary, emissions of carbon dioxide and of halocarbons from mobile air conditioners have been globally increasing and are further expected to grow. Consequently, road transport''s impact on climate is gaining in importance. The expected efficiency improvements of vehicles and the introduction of biofuels will not be sufficient to offset the expected strong growth in both, passenger and freight transportation. Technical measures could offer a significant reduction potential, but strong interventions would be needed as markets do not initiate the necessary changes. Further reductions would need a resolute expansion of low-carbon fuels, a tripling of vehicle fuel efficiency and a stagnation in absolute transport volumes. Land transport will remain a key sector in climate change mitigation during the next decades. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
16. 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.
- Author
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Borrego, Carlos, Norman, Ann-Lise, Halenka, Tomas, Eben, Krystof, Brechler, Josef, Bednar, Jan, Jurus, Pavel, Belda, Michal, and Pelikan, Emil
- Abstract
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. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
17. On the impact of urban canopy forcing on the vertical turbulent transport of pollutants.
- Author
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Huszar, Peter, Doubalova, Jana, Karlicky, Jan, Belda, Michal, Halenka, Tomas, and Sindelarova, Katerina
- Published
- 2019
18. Urbanization of weather forecast, air-quality and climate scenarios for Prague - Project URBI PRAGENSI.
- Author
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Halenka, Tomas, Belda, Michal, Huszar, Peter, Karlicky, Jan, Novakova, Tereza, and Zak, Michal
- Subjects
- *
WEATHER forecasting , *URBANIZATION , *CLIMATOLOGY - Published
- 2018
19. On the role of urbanization in weather (and air/quality) forecasting.
- Author
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Halenka, Tomas, Belda, Michal, Huszar, Peter, Karlicky, Jan, and Novakova, Tereza
- Subjects
- *
URBANIZATION , *FORECASTING , *WEATHER - Published
- 2018
20. Urbanization in convection permitting simulations.
- Author
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Belda, Michal, Halenka, Tomas, and Novakova, Tereza
- Subjects
- *
URBANIZATION - Published
- 2018
21. Urban heat island of Prague in changing climate.
- Author
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Zak, Michal, Belda, Michal, and Halenka, Tomas
- Published
- 2018
22. High resolution regional climate change modelling in CECILIA Project – climate change signal in central and Eastern Europe.
- Author
-
Halenka, Tomas, Miksovsky, J., Belda, M., and Huszar, P.
- Published
- 2009
- Full Text
- View/download PDF
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