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5 results on '"Department of Environmental Science and Engineering [Pasadena] (ESE)"'

1. Cloud microphysics and aerosol indirect effects in the global climate model ECHAM5-HAM

Author

J. Zhang, Corinna Hoose, Silvia Kloster, Erich Roeckner, Sylvaine Ferrachat, Ulrike Lohmann, Philip Stier, Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Environmental Science and Engineering [Pasadena] (ESE), California Institute of Technology (CALTECH), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, and Meteorological Service of Canada

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, Cloud cover, 0207 environmental engineering, 02 engineering and technology, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, lcsh:Chemistry, Relative humidity, Emission inventory, 020701 environmental engineering, Sea salt aerosol, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Ice crystals, lcsh:QC1-999, Aerosol, lcsh:QD1-999, 13. Climate action, Liquid water content, Cloud albedo, Environmental science, lcsh:Physics, Caltech Library Services
Abstract

The double-moment cloud microphysics scheme from ECHAM4 that predicts both the mass mixing ratios and number concentrations of cloud droplets and ice crystals has been coupled to the size-resolved aerosol scheme ECHAM5-HAM. ECHAM5-HAM predicts the aerosol mass, number concentrations and mixing state. The simulated liquid, ice and total water content and the cloud droplet and ice crystal number concentrations as a function of temperature in stratiform mixed-phase clouds between 0 and −35° C agree much better with aircraft observations in the ECHAM5 simulations. ECHAM5 performs better because more realistic aerosol concentrations are available for cloud droplet nucleation and because the Bergeron-Findeisen process is parameterized as being more efficient. The total anthropogenic aerosol effect includes the direct, semi-direct and indirect effects and is defined as the difference in the top-of-the-atmosphere net radiation between present-day and pre-industrial times. It amounts to −1.9 W m−2 in ECHAM5, when a relative humidity dependent cloud cover scheme and aerosol emissions representative for the years 1750 and 2000 from the AeroCom emission inventory are used. The contribution of the cloud albedo effect amounts to −0.7 W m−2. The total anthropogenic aerosol effect is larger when either a statistical cloud cover scheme or a different aerosol emission inventory are employed because the cloud lifetime effect increases.

Published
2007

2. Aerosol absorption and radiative forcing

Author

Stefan Kinne, John H. Seinfeld, Philip Stier, Olivier Boucher, Department of Environmental Science and Engineering [Pasadena] (ESE), California Institute of Technology (CALTECH), Department of Chemical Engineering, Department of chemical engineering, Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft, Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], EGU, Publication, and Union, European Geosciences

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Atmospheric,Oceanic,and Planetary physics, Environment, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, complex mixtures, lcsh:Chemistry, Engineering & allied sciences, Radiative transfer, Climate systems and policy, Optical depth, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric models, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, Physics, Radiative forcing, respiratory system, lcsh:QC1-999, Chemical and process engineering, Aerosol, AERONET, lcsh:QD1-999, 13. Climate action, Effective medium approximations, Environmental science, Climate model, lcsh:Physics, Caltech Library Services
Abstract

We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006) significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA) radiative forcing clear-sky from −0.79 to −0.53 W m−2 (33%) and all-sky from −0.47 to −0.13 W m−2 (72%). Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m−2 (36%) clear-sky and of 0.12 W m−2 (92%) all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W m−2 and a positive TOA forcing perturbation of 0.02 W m−2. The long-wave aerosol radiative effects are small for anthropogenic aerosols but become of relevance for the larger natural dust and sea-salt aerosols.

Published
2007

3. The effect of harmonized emissions on aerosol properties in global models – an AeroCom experiment

Author

Maarten Krol, M. S. Reddy, Olivier Boucher, Dorothy Koch, Alf Grini, Stefan Kinne, Sunling Gong, Joyce E. Penner, V. Montanaro, Alf Kirkevåg, Michael Schulz, Gunnar Myhre, Mian Chin, Ivar S. A. Isaksen, C. Textor, Giovanni Pitari, Toshihiko Takemura, Philip Stier, D. Fillmore, Silvia Kloster, Jean-Francois Lamarque, Susanne E. Bauer, Yves Balkanski, Tore F. Berglen, Terje Koren Berntsen, Johann Feichter, Thomas Diehl, Frank Dentener, Axel Lauer, Sarah Guibert, Johannes Hendricks, P. Huang, X. Tie, Jón Egill Kristjánsson, Paul Ginoux, Xiaohong Liu, Øyvind Seland, Larry W. Horowitz, Trond Iversen, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft, Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Columbia University [New York], University of Oslo (UiO), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], NASA Goddard Space Flight Center (GSFC), JRC Institute for Environment and Sustainability (IES), European Commission - Joint Research Centre [Ispra] (JRC), Goddard Earth Sciences and Technology Center (GEST), University of Maryland [Baltimore County] (UMBC), University of Maryland System-University of Maryland System, National Center for Atmospheric Research [Boulder] (NCAR), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA), ARQM Meteorological Service Canada, Environment and Climate Change Canada, DLR Institut für Physik der Atmosphäre (IPA), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), Institute for Marine and Atmospheric Research [Utrecht] (IMAU), Utrecht University [Utrecht], University of Michigan [Ann Arbor], University of Michigan System, Pacific Northwest National Laboratory (PNNL), University of L'Aquila [Italy] (UNIVAQ), Department of Environmental Science and Engineering [Pasadena] (ESE), California Institute of Technology (CALTECH), Kyushu University [Fukuoka], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Kyushu University, Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Lille, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Met Office Hadley Centre (MOHC), European Commission [Brussels], Goddard Earth Sciences and Technology and Research (GESTAR), NASA-Universities Space Research Association (USRA), and Battelle

Subjects
Meteorologie en Luchtkwaliteit, Atmospheric Science, food.ingredient, Meteorology and Air Quality, Meteorology, 010504 meteorology & atmospheric sciences, transport model, Air pollution, general-circulation model, 010501 environmental sciences, Mineral dust, medicine.disease_cause, Atmospheric sciences, size, 01 natural sciences, lcsh:Chemistry, food, sulfate aerosols, medicine, wet deposition, climate, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, mineral dust, WIMEK, Microphysics, 010505 oceanography, Sea salt, emissions, respiratory system, simulation, lcsh:QC1-999, ground measurements, Aerosol, global models, optical-properties, Deposition (aerosol physics), lcsh:QD1-999, [SDU]Sciences of the Universe [physics], 13. Climate action, General Circulation Model, Particle, Dynamik der Atmosphäre, lcsh:Physics, aerosols, Caltech Library Services
Abstract

The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA) and one with unified emissions, injection heights, and particle sizes at the source (ExpB). Surprisingly, harmonization of aerosol sources has only a small impact on the simulated inter-model diversity of the global aerosol burden, and consequently global optical properties, as the results are largely controlled by model-specific transport, removal, chemistry (leading to the formation of secondary aerosols) and parameterizations of aerosol microphysics (e.g., the split between deposition pathways) and to a lesser extent by the spatial and temporal distributions of the (precursor) emissions. The burdens of black carbon and especially sea salt become more coherent in ExpB only, because the large ExpA diversities for these two species were caused by a few outliers. The experiment also showed that despite prescribing emission fluxes and size distributions, ambiguities in the implementation in individual models can lead to substantial differences. These results indicate the need for a better understanding of aerosol life cycles at process level (including spatial dispersal and interaction with meteorological parameters) in order to obtain more reliable results from global aerosol simulations. This is particularly important as such model results are used to assess the consequences of specific air pollution abatement strategies.

Published
2007
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4. International Consortium for Atmospheric Research on Transport and Transformations (ICARTT): North America to Europe - Overview of the 2004 summer field study

Author

Timothy S. Bates, Richard E. Honrath, Philip B. Russell, R. Zbinden, Stuart A. McKeen, Robert W. Talbot, J. F. Meagher, Kathy S. Law, Fred C. Fehsenfeld, Richard Leaitch, Allen H. Goldstein, Hans Schlager, Alastair C. Lewis, D. D. Parrish, Alexander A. P. Pszenny, Gérard Ancellet, R. M. Hardesty, John H. Seinfeld, NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), Department of Environmental Science, Policy, and Management [Berkeley] (ESPM), University of California [Berkeley], University of California-University of California, Department of Civil and Environmental Engineering [Michigan] (CEE), Michigan Technological University (MTU), Department of Chemistry [York, UK], University of York [York, UK], Environment and Climate Change Canada, Institute for the Study of Earth, Oceans, and Space [Durham] (EOS), University of New Hampshire (UNH), Mount Washington Observatory (MWOBS), NASA Ames Research Center (ARC), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), Department of Environmental Science and Engineering [Pasadena] (ESE), California Institute of Technology (CALTECH), Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Earth's energy budget, Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, air pollution, Soil Science, 010501 environmental sciences, Aquatic Science, Oceanography, 01 natural sciences, Troposphere, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Air quality index, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], long-range transport, Ecology, Paleontology, Forestry, ICARTT, Field (geography), Atmospheric research, ozone, nitrogen oxides, Geophysics, Lidar, 13. Climate action, Space and Planetary Science, Western europe, Environmental science, Satellite
Abstract

In the summer of 2004 several separate field programs intensively studied the photochemical, heterogeneous chemical and radiative environment of the troposphere over North America, the North Atlantic Ocean, and western Europe. Previous studies have indicated that the transport of continental emissions, particularly from North America, influences the concentrations of trace species in the troposphere over the North Atlantic and Europe. An international team of scientists, representing over 100 laboratories, collaborated under the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) umbrella to coordinate the separate field programs in order to maximize the resulting advances in our understanding of regional air quality, the transport, chemical transformation and removal of aerosols, ozone, and their precursors during intercontinental transport, and the radiation balance of the troposphere. Participants utilized nine aircraft, one research vessel, several ground-based sites in North America and the Azores, a network of aerosol-ozone lidars in Europe, satellites, balloon borne sondes, and routine commercial aircraft measurements. In this special section, the results from a major fraction of those platforms are presented. This overview is aimed at providing operational and logistical information for those platforms, summarizing the principal findings and conclusions that have been drawn from the results, and directing readers to specific papers for further details.

Published
2006
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5. Hygroscopicity of secondary organic aerosols formed by oxidation of cycloalkenes, monoterpenes, sesquiterpenes, and related compounds

Author

Varutbangkul, V., Brechtel, Fj, Bahreini, R., Ng, Nl, Keywood, Md, Kroll, Jh, Flagan, Rc, Seinfeld, Jh, Lee, A., Allen Goldstein, EGU, Publication, Department of Chemical Engineering, California Institute of Technology (CALTECH), Brechtel Manufacturing Inc., Department of Environmental Science and Engineering [Pasadena] (ESE), National Oceanic and Atmospheric Administration (NOAA), Commonwealth Scientific and Industrial Research Organisation, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Department of Environmental Science, and Policy and Management

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, 13. Climate action, 010501 environmental sciences, 01 natural sciences, behavioral disciplines and activities, 6. Clean water, Caltech Library Services, 0105 earth and related environmental sciences
Abstract

A series of experiments has been conducted in the Caltech indoor smog chamber facility to investigate the water uptake properties of aerosol formed by oxidation of various organic precursors. Secondary organic aerosol (SOA) from simple and substituted cycloalkenes (C5-C8) is produced in dark ozonolysis experiments in a dry chamber (RH~5%). Biogenic SOA from monoterpenes, sesquiterpenes, and oxygenated terpenes is formed by photooxidation in a humid chamber (~50% RH). Using the hygroscopicity tandem differential mobility analyzer (HTDMA), we measure the diameter-based hygroscopic growth factor (GF) of the SOA as a function of time and relative humidity. All SOA studied is found to be slightly hygroscopic, with smaller water uptake than that of typical inorganic aerosol substances. The aerosol water uptake increases with time early in the experiments for the cycloalkene SOA, but decreases with time for the biogenic SOA. This behavior could indicate competing effects between the formation of more highly oxidized polar compounds (more hygroscopic), and formation of longer-chained oligomers (less hygroscopic). All SOA also exhibit a smooth water uptake with RH with no deliquescence or efflorescence. The water uptake curves are found to be fitted well with an empirical three-parameter functional form. The measured pure organic GF values at 85% RH are between 1.09?1.16 for SOA from ozonolysis of cycloalkenes, 1.01?1.04 for sesquiterpene photooxidation SOA, and 1.06?1.11 for the monoterpene and oxygenated terpene SOA. The GF of pure SOA (GForg) in experiments in which inorganic seed aerosol is used is determined by assuming volume-weighted water uptake (Zdanovskii-Stokes-Robinson or ''ZSR'' approach) and using the size-resolved organic mass fraction measured by the Aerodyne Aerosol Mass Spectrometer. Knowing the water content associated with the inorganic fraction yields GForg values. However, for each precursor, the GForg values computed from different HTDMA-classified diameters agree with each other to varying degrees. Lack of complete agreement may be a result of the non-idealities of the solutions that are not captured by the ZSR method. Comparing growth factors from different precursors, we find that GForg is inversely proportional to the precursor molecular weight and SOA yield, which is likely a result of the fact that higher-molecular weight precursors tend to produce larger and less hygroscopic oxidation products.

Published
2006

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