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6 results on '"off-line model"'

1. The mass and number size distributions of black carbon aerosol over Europe

Author

Michael Flynn, Dantong Liu, Gavin R. McMeeking, Dominick V. Spracklen, Carly Reddington, Graham Mann, Maria G. Frontoso, Hugh Coe, and Kenneth S. Carslaw

Subjects
Atmospheric Science, Particle number, Meteorology, mixing state, climate model, Atmospheric sciences, medicine.disease_cause, particle soot photometer, lcsh:Chemistry, medicine, Mass concentration (chemistry), Cloud condensation nuclei, global scales, Optical depth, elemental carbon, particulate matter, Chemistry, quality interactions eucaari, boundary-layer, Radiative forcing, lcsh:QC1-999, Soot, Aerosol, cloud condensation nuclei, lcsh:QD1-999, Particle, off-line model, lcsh:Physics
Abstract

Black carbon-containing aerosol particles play an important role in the direct and indirect radiative forcing of climate. However, the magnitude and sign of the net radiative effect is strongly dependent on the physical properties of the black carbon (BC) component of the particles, such as mass concentration, number size distribution and mixing state. Here we use a global aerosol model combined with aircraft measurements of BC particle number and size from the Single Particle Soot Photometer (SP2) to assess the realism with which these physical properties are predicted by global models. The comparison reveals a substantial mismatch between the measured and modelled BC size distribution over the size range of the SP2 instrument (90–400 nm BC diameter). The model predicts BC particle number concentrations a factor ~3.5–5.7 higher than measured and a mode diameter that is ~40–65 nm smaller than observed. More than ~90% of the model particles with dry diameters ≳260 nm contain BC, while the observations suggest only 14% on average. These model–observation biases in the BC properties are considerably greater than for the overall particle distribution, suggesting that the discrepancy is associated with model assumptions about the size and mixing state of the emitted carbonaceous particles. We expect the discrepancy in BC size distribution to be common among most global aerosol models, with implications for model estimates of absorption optical depth and direct radiative forcing.

Published
2013
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2. Intercomparison and evaluation of global aerosol microphysical properties among AeroCom models of a range of complexity

Author

Markku Kulmala, Jos Lelieveld, Gan Luo, Elisabetta Vignati, Ari Asmi, Michael Schulz, T. P. C. van Noije, Harri Kokkola, Xiaohong Liu, Kai Zhang, Richard C. Easter, Lindsay Lee, Holger Tost, S. G. Jennings, Fangqun Yu, K. Tsigaridis, Dominick V. Spracklen, John L. Gras, A. Strunk, S. J. Ghan, David A. Ridley, Mohit Dalvi, U. Kaminski, Markus Fiebig, Y. H. Lee, Urs Baltensperger, Nikos Mihalopoulos, Carly Reddington, K. von Salzen, Y. Viisanen, Colin D. O'Dowd, Roy M. Harrison, Graham Mann, J. S. Henzing, Nicolas Bellouin, Jost Heintzenberg, Matthew T. Woodhouse, David C. S. Beddows, Erik Swietlicki, Kenneth S. Carslaw, Tommi Bergman, Peter Adams, Hans-Christen Hansson, Philip Stier, John A. Ogren, V. Zdimal, Vidmantas Ulevicius, Susanne E. Bauer, Ann E. Clarke, Kirsty J. Pringle, Colin E. Johnson, Andreas Petzold, Massachusetts Institute of Technology. Department of Civil and Environmental Engineering, and Ridley, David Andrew

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Particle number, general-circulation model, mixing state, 010501 environmental sciences, Environment, climate model, black carbon, Atmospheric sciences, 01 natural sciences, Troposphere, lcsh:Chemistry, Zeppelinobservatoriet, Urban Development, ddc:550, Cloud condensation nuclei, Built Environment, number size distributions, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Microphysics, particle formation, Earth / Environmental, Cloud physics, atmospheric aerosol, CAS - Climate, Air and Sustainability, Radiative forcing, lcsh:QC1-999, Aerosol, cloud condensation nuclei, marine boundary-layer, lcsh:QD1-999, 13. Climate action, Climatology, Environmental science, Climate model, ELSS - Earth, Life and Social Sciences, off-line model, lcsh:Physics
Abstract

Many of the next generation of global climate models will include aerosol schemes which explicitly simulate the microphysical processes that determine the particle size distribution. These models enable aerosol optical properties and cloud condensation nuclei (CCN) concentrations to be determined by fundamental aerosol processes, which should lead to a more physically based simulation of aerosol direct and indirect radiative forcings. This study examines the global variation in particle size distribution simulated by 12 global aerosol microphysics models to quantify model diversity and to identify any common biases against observations. Evaluation against size distribution measurements from a new European network of aerosol supersites shows that the mean model agrees quite well with the observations at many sites on the annual mean, but there are some seasonal biases common to many sites. In particular, at many of these European sites, the accumulation mode number concentration is biased low during winter and Aitken mode concentrations tend to be overestimated in winter and underestimated in summer. At high northern latitudes, the models strongly underpredict Aitken and accumulation particle concentrations compared to the measurements, consistent with previous studies that have highlighted the poor performance of global aerosol models in the Arctic. In the marine boundary layer, the models capture the observed meridional variation in the size distribution, which is dominated by the Aitken mode at high latitudes, with an increasing concentration of accumulation particles with decreasing latitude. Considering vertical profiles, the models reproduce the observed peak in total particle concentrations in the upper troposphere due to new particle formation, although modelled peak concentrations tend to be biased high over Europe. Overall, the multi-model-mean data set simulates the global variation of the particle size distribution with a good degree of skill, suggesting that most of the individual global aerosol microphysics models are performing well, although the large model diversity indicates that some models are in poor agreement with the observations. Further work is required to better constrain size-resolved primary and secondary particle number sources, and an improved understanding of nucleation and growth (e.g. the role of nitrate and secondary organics) will improve the fidelity of simulated particle size distributions.

Published
2014
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3. Simulating ultrafine particle formation in Europe using a regional CTM: Contribution of primary emissions versus secondary formation to aerosol number concentrations

Author

Marcel M. Moerman, Ilona Riipinen, Colin D. O'Dowd, H.A.C. Denier van der Gon, Alfred Wiedensohler, J. P. Putaud, P. E. Charalampidis, Christodoulos Pilinis, Christos Fountoukis, and Spyros N. Pandis

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Particle number, three-dimensional modeling, Nucleation, Balkans, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, ammonia, air-quality, lcsh:Chemistry, Urban Development, emission control, ion-induced nucleation, Ultrafine particle, size distribution, Mass concentration (chemistry), sulfur dioxide, Built Environment, chemical-transport model, concentration (composition), Emission Environment, size distributions, particle size, lcsh:QC1-999, cloud condensation nuclei, Climatology, EELS - Earth, Environmental and Life Sciences, transport process, Chemical transport model, nucleation, Earth & Environment, aerosol formation, wild-land fires, Scanning mobility particle sizer, global scales, 0105 earth and related environmental sciences, Portugal, quality interactions eucaari, CAS - Climate, Air and Sustainability, Aerosol, lcsh:QD1-999, 13. Climate action, Spain, Environmental science, atmospheric sulfuric-acid, Particle size, off-line model, lcsh:Physics
Abstract

A three-dimensional regional chemical transport model (CTM) with detailed aerosol microphysics, PMCAMx-UF, was applied to the European domain to simulate the contribution of direct emissions and secondary formation to total particle number concentrations during May 2008. PMCAMx-UF uses the Dynamic Model for Aerosol Nucleation and the Two-Moment Aerosol Sectional (TOMAS) algorithm to track both aerosol number and mass concentration using a sectional approach. The model predicts nucleation events that occur over scales of hundreds up to thousands of kilometers especially over the Balkans and Southeast Europe. The model predictions were compared against measurements from 7 sites across Europe. The model reproduces more than 70% of the hourly concentrations of particles larger than 10 nm (N10) within a factor of 2. About half of these particles are predicted to originate from nucleation in the lower troposphere. Regional nucleation is predicted to increase the total particle number concentration by approximately a factor of 3. For particles larger than 100 nm the effect varies from an increase of 20% in the eastern Mediterranean to a decrease of 20% in southern Spain and Portugal resulting in a small average increase of around 1% over the whole domain. Nucleation has a significant effect in the predicted N50 levels (up to a factor of 2 increase) mainly in areas where there are condensable vapors to grow the particles to larger sizes. A semi-empirical ternary sulfuric acid-ammonia-water parameterization performs better than the activation or the kinetic parameterizations in reproducing the observations. Reducing emissions of ammonia and sulfur dioxide affects certain parts of the number size distribution.

Published
2012

4. Primary versus secondary contributions to particle number concentrations in the European boundary layer

Author

Karine Sellegri, Nadezda Zikova, Kenneth S. Carslaw, Ernest Weingartner, Angela Marinoni, Thomas Hamburger, Thomas Tuch, Paolo Bonasoni, Joonas Merikanto, Urs Baltensperger, A. Sonntag, Marcel M. Moerman, M. G. Frontoso, Colin D. O'Dowd, Vladimír Ždímal, Pasi Aalto, Pontus Roldin, J. Boulon, L. Collins, Carly Reddington, Birgit Wehner, Hugh Coe, Wolfram Birmili, J. P. Putaud, Andreas Minikin, R. Duchi, Christian Plass-Dülmer, Hans-Christen Hansson, Régis Dupuy, Carsten Gruening, Paolo Laj, Markku Kulmala, Peter Tunved, J. S. Henzing, Dominick V. Spracklen, Alfred Wiedensohler, Nikos Mihalopoulos, Erik Swietlicki, S. G. Jennings, Giorgos Kouvarakis, Harald Flentje, Institute for Climate and Atmospheric Science [Leeds] (ICAS), School of Earth and Environment [Leeds] (SEE), University of Leeds-University of Leeds, C2SM, Department of Physics [Helsinki], Falculty of Science [Helsinki], Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, DLR Institut für Physik der Atmosphäre (IPA), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), School of Earth, Atmospheric and Environmental Sciences [Manchester] (SEAES), University of Manchester [Manchester], Deutscher Wetterdienst [Offenbach] (DWD), Leibniz Institute for Tropospheric Research (TROPOS), Centre for Climate and Air Pollution Studies [Galway] (C-CAPS), National University of Ireland [Galway] (NUI Galway), School of Physics [NUI Galway], Laboratory of Atmospheric Chemistry [Paul Scherrer Institute] (LAC), Paul Scherrer Institute (PSI), Institute for Applied Environmental Research [Stockholm], Stockholm University, Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de météorologie physique (LaMP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), JRC Institute for Environment and Sustainability (IES), European Commission - Joint Research Centre [Ispra] (JRC), Division of Nuclear Physics, Lund University [Lund], Netherlands Organization for Applied Scientific Research (TNO), TNO Science and Industry, Environmental Chemical Processes Laboratory [Heraklion] (ECPL), Department of Chemistry [Heraklion], University of Crete [Heraklion] (UOC)-University of Crete [Heraklion] (UOC), Institute of Chemical Process Fundamentals of the AS CR, CNR Institute of Atmospheric Sciences and Climate (ISAC), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), NERC ADIENT, University of Helsinki-University of Helsinki, Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Consiglio Nazionale delle Ricerche (CNR), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Atmospheric Science, Particle number, 010504 meteorology & atmospheric sciences, aerosol particles, Aerosol radiative forcing, Earth & Environment, Nucleation, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, boundary layer, Environment, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, resolved aerosol microphysics, lcsh:Chemistry, Primary (astronomy), ion-induced nucleation, instrumental development, Cloud condensation nuclei, 0105 earth and related environmental sciences, particulate matter, size distributions, Atmosphärische Spurenstoffe, Particulates, lcsh:QC1-999, Aerosol, on-road, Europe, Boundary layer, carbonaceous aerosol, lcsh:QD1-999, 13. Climate action, UES - Urban Environment & Safety, Environmental science, emission factors, atmospheric sulfuric-acid, off-line model, EELS - Earth, Environmental and Life Sciences, lcsh:Physics
Abstract

It is important to understand the relative contribution of primary and secondary particles to regional and global aerosol so that models can attribute aerosol radiative forcing to different sources. In large-scale models, there is considerable uncertainty associated with treatments of particle formation (nucleation) in the boundary layer (BL) and in the size distribution of emitted primary particles, leading to uncertainties in predicted cloud condensation nuclei (CCN) concentrations. Here we quantify how primary particle emissions and secondary particle formation influence size-resolved particle number concentrations in the BL using a global aerosol microphysics model and aircraft and ground site observations made during the May 2008 campaign of the European Integrated Project on Aerosol Cloud Climate Air Quality Interactions (EUCAARI). We tested four different parameterisations for BL nucleation and two assumptions for the emission size distribution of anthropogenic and wildfire carbonaceous particles. When we emit carbonaceous particles at small sizes (as recommended by the Aerosol Intercomparison project, AEROCOM), the spatial distributions of campaign-mean number concentrations of particles with diameter >50 nm (N50) and >100 nm (N100) were well captured by the model (R2≥0.8) and the normalised mean bias (NMB) was also small (−18% for N50 and −1% for N100). Emission of carbonaceous particles at larger sizes, which we consider to be more realistic for low spatial resolution global models, results in equally good correlation but larger bias (R2≥0.8, NMB = −52% and −29%), which could be partly but not entirely compensated by BL nucleation. Within the uncertainty of the observations and accounting for the uncertainty in the size of emitted primary particles, BL nucleation makes a statistically significant contribution to CCN-sized particles at less than a quarter of the ground sites. Our results show that a major source of uncertainty in CCN-sized particles in polluted European air is the emitted size of primary carbonaceous particles. New information is required not just from direct observations, but also to determine the "effective emission size" and composition of primary particles appropriate for different resolution models., JRC.H.2-Air and Climate

Published
2011
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5. Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

Author

Dominick V. Spracklen, Nikos Mihalopoulos, Robert W. Talbot, S. G. Jennings, Niku Kivekäs, Graham Mann, J. Sun, Robert A. Weller, Radovan Krejci, Colin D. O'Dowd, Wolfram Birmili, Boris Bonn, Ari Laaksonen, John A. Ogren, Heikki Lihavainen, S. J. Pickering, Andreas Minikin, John L. Gras, Karine Sellegri, Urs Baltensperger, Elisabeth Andrews, Ernest Weingartner, A. Wiedensohler, Kenneth S. Carslaw, Carly Reddington, Roy M. Harrison, Lauri Laakso, Mika Komppula, Paolo Laj, Michael Boy, Markku Kulmala, A. Hamed, Giorgos Kouvarakis, Joonas Merikanto, Institute for Atmospheric Science [Leeds], School of Earth and Environment [Leeds] (SEE), University of Leeds-University of Leeds, ESRL Global Monitoring Laboratory [Boulder] (GML), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), Laboratory of Atmospheric Chemistry [Paul Scherrer Institute] (LAC), Paul Scherrer Institute (PSI), Univ. of Helsinki, Dept. of Physics, Finnish Meteorological Institute (FMI), Kuopio Unit [FMI], Environmental Chemistry Laboratory [Crete], University of Crete [Heraklion] (UOC), Department of Experimental Physics, Leibniz Institute for Tropospheric Research (TROPOS), Leibniz-Institut für Troposphärenforschung (TROPOS), Department of Bentho-pelagic processes, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), CSIRO Marine and Atmospheric Research, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Physique (LaMP), Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute for Atmospheric and Environmental Sciences [Frankfurt/Main] (IAU), Goethe-University Frankfurt am Main, Department of Meteorology, Stockholm University, Department of Physics, University of Kuopio, DLR Institut für Physik der Atmosphäre (IPA), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), School of Geography, Earth and Environmental Sciences [Birmingham], University of Birmingham [Birmingham], Climate Change Research Center [Durham], University of New Hampshire (UNH), Centre for Atmosphere Watch and Services [Beijing] (CAWAS), Chinese Academy of Meteorological Sciences (CAMS), NERC Advanced Fellowship NERC APPRAISE NERC AEROFORM NE/D01395X/1 EUCAARI, ESRL Global Monitoring Division [Boulder] (GMD), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Physique - Clermont Auvergne (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), National Centre for Atmospheric Science, School of Geography, Climate Change Research Center, Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, nucleation mode particles, 010504 meteorology & atmospheric sciences, Particle number, aerosol, Analytical chemistry, Nucleation, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, Troposphere, lcsh:Chemistry, size-resolved aerosol, free troposphere, ddc:550, Cloud condensation nuclei, boreal forest, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, 0105 earth and related environmental sciences, Microphysics, Chemistry, particle formation, remote troposphere, Atmosphärische Spurenstoffe, boundary-layer, lcsh:QC1-999, Aerosol, Boundary layer, CN, cloud condensation nuclei, coastal environment, troposphere, lcsh:QD1-999, 13. Climate action, Particle, atmospheric sulfuric-acid, off-line model, lcsh:Physics
Abstract

We synthesised observations of total particle number (CN) concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300–2000 cm−3 in the marine boundary layer and free troposphere (FT) and 1000–10 000 cm−3 in the continental boundary layer (BL). Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2–10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46) but fail to explain the observed seasonal cycle (R2=0.1). The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=−88%) unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%). Simulated CN concentrations in the continental BL were also biased low (NMB=−74%) unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one) or kinetic-type mechanism (J proportional to sulfuric acid to the power two) with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3) than by increasing the number emission from primary anthropogenic sources (R2=0.18). The nucleation constants that resulted in best overall match between model and observed CN concentrations were consistent with values derived in previous studies from detailed case studies at individual sites. In our model, kinetic and activation-type nucleation parameterizations gave similar agreement with observed monthly mean CN concentrations.

Published
2010
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6. Interaction-based feature-driven model-transformations for generating e-forms

Author

Bedir Tekinerdoǧan and Namik Aktekin

Subjects
Theoretical computer science, Computer science, E-forms, Model transformation, Interactive approach, Context (language use), E-government, Model-driven software development, computer.software_genre, Closed world assumption, Domain (software engineering), Runtimes, Computer software, Software design, computer.programming_language, Off-line model, business.industry, Software development, Domain model, Domain modeling, End users, Feature models, Closed-world assumption, Transformation (function), Data mining, Feature-oriented modeling, business, computer, Shear deformation, Government data processing
Abstract

Date of Conference: 06-06 October , 2009 Conference name: FOSD '09 Proceedings of the First International Workshop on Feature-Oriented Software Development One of the basic pillars in Model-Driven Software Development (MDSD) is defined by model transformations and likewise several useful approaches have been proposed in this context. In parallel, domain modeling plays an essential role in MDSD to support the definition of concepts in the domain, and support the model transformation process. In this paper, we will discuss the results of an e-government project for the generation of e-forms from feature models. Very often existing model transformation practices seem to largely adopt a closed world assumption whereby the transformation definitions of models are defined beforehand and interaction with the user at run-time is largely omitted. Our study shows the need for a more interactive approach in model transformations in which e-forms are generated after interaction with the end-user. To show the case we illustrate three different approaches for generation in increasing complexity: (1) offline model transformation without interaction (2) model transformation with initial interaction (3) model-transformation with run-time interaction. Copyright©2009 ACM.

Published
2009
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