Atmospheric Integrated Research at University of California, Irvine

Simulations of Air / Water Pollution and Climate

James T. Randerson

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Ralph J. and Carol M. Cicerone Professor, Earth System Science (Ph.D. in Biological Sciences, Stanford University, 1998)
Prof. Randerson's storied career brings considerable expertise in the study of the global carbon cycle using remote sensing and in-situ measurements and different types of models. Current research themes in his laboratory include climate-carbon cycle feedbacks, land use change, and the effects of fire on ecosystem function and atmospheric composition. He has conducted field work in Alaska and Siberia to assess the long-term impacts of fire on surface energy exchange and fluxes of carbon dioxide. After serving as faculty at Caltech, in 2003 James moved to UC Irvine where he now holds the position of Ralph J. and Carol M. Cicerone Professor of Earth System Science. He serves as a member of the Biological and Environmental Research Federal Advisory Committee for the U.S. Dept. of Energy, Office of Science.

Research Interests: 

Climate-carbon cycle feedbacks, fires, land cover change, remote sensing, tropical deforestation, global change in arctic and boreal ecosystems, terrestrial ecosystems and climate policy

Selected Honors and Awards: 
American Geophysical Union: James B. Macelwane Medal, 2005
American Geophysical Union: Piers J. Sellers Global Environmental Change Mid-Career Award, 2017
Fellow, American Geophysical Union
Member, U.S. National Academy of Sciences

Claudia Czimczik

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Office Location: 3228 Croul Hall

Lab Location: 2222 Croul Hall

Lab Phone: 949-824-3444


Group site:


Prof. Czimczik Green‘s research aims at understanding the impacts of climate change, alterations in natural disturbance frequencies (i.e. fire), and changes in land use and management (i.e. urbanization) on the cycling of carbon and nitrogen in terrestrial ecosystems. Her research seeks to appreciate and predict how human activities will impact the functioning of terrestrial ecosystems in the future and how changing terrestrial ecosystems will feed back to the climate system.  A major focus of these activities is on high-latitude ecosystems, i.e. arctic tundra and boreal forests.
To obtain these results and meet these goals, her group utilizes a variety of geochemical tools including trace gas analysis and stable- and radio-isotope analysis. The work has a very strong foundation of field observations – they use both unmanipulated research sites (e.g. natural gradients, chronosequences) and actively manipulated research sites.
She received her undergraduate and graduate education in Germany, and obtained a Diploma in Geoecology from the University of Bayreuth (1999) and a Ph.D from the Max-Planck-Institute for Biogeochemistry and Friedrich-Schiller-University (2003) in Jena. She joined UCI’s Department of Earth System Science (ESS) as a researcher in 2003, and the faculty in 2011.

Research Interests: 
  • Studies the impacts of climate change, alterations in natural disturbance frequencies (i.e. fire) and changes in land use and management (i.e. urbanization) on the cycling of carbon and nitrogen in terrestrial ecosystems.
  • Comprehends and predicts how human activities will impact the functioning of terrestrial ecosystems in the future and how changing terrestrial ecosystems will feedback to the climate system.
  • Focuses on high-latitude ecosystems (arctic tundra and boreal forests).
  • Expert in how climate and land-use change affect the storage of carbon in land ecosystems and the exchange of carbon dioxide, methane and carbonaceous aerosols between the land and the atmosphere. Key interests: Boreal and Arctic, Mega-Cities.

Research Areas: Biogeochemical Cycles


Celia Faiola

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Department of Ecology and Evolutionary Biology
463 Steinhaus Hall
University of California
Irvine, California 92697-2525


Ecological climatology is the interdisciplinary study of the physical, chemical, and biological processes that influence interactions between terrestrial ecosystems and climate.
One biosphere-atmosphere interaction with important implications for climate is the production of atmospheric aerosol via oxidation of plant volatile emissions. Atmospheric aerosol are the small solid or liquid particles that are suspended in the atmosphere.  They influence climate directly by scattering the sun's radiation, or indirectly by acting as cloud condensation nuclei and affecting cloud formation processes.  A sub-set of atmospheric aerosol, called secondary organic aerosol, is formed via gas-phase oxidation of organic compounds which generates reaction products that  partition to the particle-phase.  Most secondary organic aerosol in the atmosphere is formed from plant volatile emissions. 
Global change is altering the environmental factors that regulate plant volatile emission rates.  In fact, one of the most challenging problems in climate change science is accurately modeling current and future secondary organic aerosol derived from these plant volatiles. 
Prof. Faiola's research investigates the biological production and release, atmospheric chemistry, and eventual fate of plant volatile emissions, and how all these components are evolving in a changing climate.  To tackle this complex problem, she uses field measurements and laboratory experiments to investigate plant stress impacts on plant volatile emissions and aerosol production at the individual plant scale.  She and her group integrate results from field and laboratory experiments into models to investigate impacts at the regional and global scale.  Accurately predicting  impacts of global change on plant-aerosol-climate interactions is vital for improving climate change mitigation policies.
Professional Association Memberships:

  • American Association for Aerosol Research (AAAR)
  • American Geophysical Union (AGU)
  • American Association for the Advancement of Science (AAAS)
  • National Science Teachers Association (NSTA)

Professional Service:

  • 2016 -      iLEAPS Regional Committee Member: North America Early Career Scientist Network
  • 2015 -      External Reviewer: National Oceanic and Atmospheric Association (NOAA), National Science Foundation (NSF)
  • 2014 -      Referee for scientific journals: Landscape and Ecological Engineering, Atmospheric Chemistry and Physics, Nature Geoscience
Research Interests: 

Plants, Atmospheric Aerosol, Global Change

Selected Honors and Awards: 
John Orsborn Outstanding Graduate Student Award in the Civil and Environmental Engineering Department, Washington State University (2014)
Harriet B. Rigas Award for Outstanding Women in Graduate Studies at the Doctoral Level (2014)

Manabu Shiraiwa

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Associate Professor of Chemistry.  ( Chemistry, Max Planck Institute for Chemistry, 2011).
Prof. Shiraiwa brings expertise in kinetic flux models for gas-particle interactions in aerosols and clouds and combines numerical modeling, laboratory experiments, and field measurements on organic aerosol and oxidant chemistry
His research focuses on the properties and multiphase processes of aerosol particles and their effects on atmospheric chemistry, air quality, and human health.  Multiphase chemistry of aerosols are efficient pathways for the formation of secondary organic aerosols (SOA) and aging.  Multiphase chemistry also deals with chemical reactions, transport processes, and transformations between gaseous, liquid, and solid matter.  These processes are essential for Earth system science and climate research as well as for life and health sciences on molecular and global levels, bridging a wide range of spatial and temporal scales from below nanometers to thousands of kilometers and from less than nanoseconds to years.  Understanding the mechanisms and kinetics of these processes is also required to address societally relevant questions of global environmental change and public health.
Key Topics:

  • Gas uptake, formation, evolution and partitioning of organic aerosols
  • Multiphase chemical processes at the atmosphere-biosphere interface including lung lining fluid and human skin
  • Reactive Oxygen Species/Intermediates (ROS/ROI), allergenic proteins and their health effects

Synergistic Activities

  • Co-editor of the journal Atmospheric Chemistry and Physics (since 2015)
  • Chair of the Aerosol Chemistry Working Group, European Aerosol Assembly (EAA) (2011 - 2016)
Research Interests: 

Atmospheric Chemistry, Heterogeneous and Multiphase Chemistry, Aerosol Particles, Reactive Oxygen Species, Kinetic Modeling

Selected Honors and Awards: 
Otto-Hahn Medal, Max Planck Society 2011
Paul-Crutzen Prize, German Chemical Society 2012
Sheldon K. Friedlander Award, American Association for Aerosol Research (AAAR) 2014
Young Scientist Award, Japan Society of Atmospheric Chemistry 2015
NSF CAREER Award, National Science Foundation, 2017
Paul Crutzen Award for Early Career Scientists, International Commission on Atmospheric Chemistry and Global Pollution (iCACGP), 2018
Make Our Planet Great Again (MOPGA) short-stay program, Campus France 2018
Walter A. Rosenblith New Investigator Award, Health Effects Institute, 2018
Environmental Science & Technology and ES&T Letters Early Career Scientist, 2019

Dr. Alex Guenther

Contact Information

Office Location: 3327 Croul Hall

Department of Earth System Science
3216 Croul Hall, Irvine, CA 92697-3100
PH: 949-824-8794


Dr. Guenther is an international leader in atmospheric and terrestrial ecosystem research who has published more than 280 peer-reviewed journal articles.  He has developed numerical models that are widely used by the scientific and regulatory communities to simulate biogenic reactive gas and aerosol emissions for air quality and climate modeling.  He has led more than 40 integrative field studies on six continents in tropical, temperate, and boreal ecosystems to provide observations to advance understanding of biogenic emissions and their role in air quality and climate.  He served as chair of the Global Emissions Inventory Activity (GEIA) and Integrated Land-Ecosystem Process Study (iLEAPS) core activities of the International Geosphere Biosphere Program (IGBP) and was a contributing author for the Third and Fourth Assessment reports of the Intergovernmental Panel on Climate Change.
He comes to us from the Pacific Northwest National Laboratory (2013-2015) where he promoted advancements in understanding the role of ecosystem-atmosphere interactions in climate change.  He also led PNNL’s Environmental Molecular Science Laboratory (EMSL) atmospheric aerosol science theme focus where his work spanned and further integrated PNNL’s extensive measurement capabilities, including the Atmospheric Measurements Laboratory and the laboratory’s diverse programs in atmospheric, ecosystem, and climate modeling.
Prior to PNNL he was Senior Scientist and Section Head, National Center for Atmospheric Research (NCAR), from 1991-2013 where he was responsible for systematic advancement of groundbreaking measurements and modeling of biogenic emissions and their impact on the earth system.  This led to his development of the Model of Emissions of Gases and Aerosols from Nature, or MEGAN, a model that is a critical component of many of the climate and air quality models used by researchers today.  In addition to its wide use in research, MEGAN is also an essential tool used by regulatory agencies including the Environmental Protection Agency.
Research areas: Simulations of Air / Water Pollution and Climate; Chemistry, Processes, and Measurements

  • Ph.D. in Civil and Environmental Engineering, Washington State University (1989)
  • M.S. in Environmental Engineering, Washington State University (1986)
  • B.S. in Biology, University of Puget Sound (1984)

Awards & Honors: 

  • 2015: Fellow of the American Geophysical Union
  • 2012:  University Corporation for Atmospheric Research Outstanding Publication Award
  • 2011:  Yoram J. Kaufman Award for Unselfish Cooperation in Research, American Geophysical Union
  • 2008:  Haagen-Smit Outstanding Publication Prize
  • 2007:  U.S. Environmental Protection Agency Science and Technological Achievement Award
  • 2004:  Elected Chair of the Gordon Conference on Biogenic Volatile Organic Compounds in the Atmosphere
Selected Honors and Awards: 
2004: Elected Chair of the Gordon Conference on Biogenic Volatile Organic Compounds in the Atmosphere
2007: U.S. Environmental Protection Agency Science and Technological Achievement Award
2008: Haagen-Smit Outstanding Publication Prize
2011: Yoram J. Kaufman Award for Unselfish Cooperation in Research, American Geophysical Union
2012: University Corporation for Atmospheric Research Outstanding Publication Award
2015: Fellow of the American Geophysical Union

Prof. Michael J. Prather

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University of California, Irvine
3329 Croul Hall
Mail Code: 3100
Irvine, CA 92697

(949) 824-5838

Professor of Earth System Science, Fred Kavli Chair [Ph.D.(Astronomy) Yale University; M.A.(Physics) Merton College, Oxon]. Professor Prather brings expertise in global atmospheric modeling, particularly as applied to atmospheric composition and climate change.

Prof. Prather’s research interest is in simulation of the physical, chemical, and biological processes that determine atmospheric composition. He focuses also on development of (1) detailed numerical models of photochemistry and atmospheric radiation, and (2) global chemical transport models that describe ozone and other trace gases. Studies include the predicted effects of volcanic sulfate aerosols on stratospheric ozone loss, the role of clouds in scattering sunlight and altering photochemistry, non-linearities in chemical systems that lead to sudden changes such as the depletion of ozone caused by CFC increases, and feedbacks in the atmosphere that alter the expected magnitude and duration of anthropogenic perturbations.

Numerical models of atmospheric chemistry must simulate the transport of trace species by winds, convective mixing, boundary layer exchange with the surface, and exchange between the stratosphere and troposphere. Such models are used to predict future changes in the atmosphere and to analyze global data sets. Observed trace gas distributions are used as measures of the atmospheric circulation or alternatively as indicators of the location and strength of sources. Such a quantitative understanding of these causal relationships is an essential element of assessments of chemical and climatic change, and it is needed to convince governments and the public to make tough environmental choices.

Research Interests: 
  • Atmospheric Chemistry
  • Composition
  • Ozone Depletion
  • Climate
Selected Honors and Awards: 
Jefferson Science Fellow, U.S. State Department, 2005/2006 (active - 2010)
Norwegian Academy of Science and Letters (Foreign Member, 1999)
Fellow of the American Geophysical Union (1997)
Fellow of the American Association for the Advancement of Science (2004)
NASA Medal for Exceptional Scientific Achievement (1992)

Prof. Donald Dabdub

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Dept. of Mechanical and Aerospace Engineering
4226 Engineering Gateway
University of California, Irvine
Irvine, CA 92697

(949) 824-6126

Professor, Department of Mechanical & Aerospace Engineering. Associate Dean, UCI Division of Undergraduate Education.
Ph. D. in Chemical Engineering from California Institute of Technology.
Professor Dabdub brings to the ORU his expertise in urban air quality modeling, including reactions in and on aerosol particles and surfaces in the urban boundary layer. In the area of atmospheric sciences, Prof. Dabdub’s research interests lie in mathematical modeling of urban and global air pollution dynamics, dynamics of atmospheric aerosols and secondary organic aerosols, chemical reactions at gas-liquid interfaces, and the impact of energy generation on air quality. His focus in the area of computational sciences is on applied mathematics, numerical algorithms on massively parallel computers, and grid-based computations. Dr. Dabdub’s modeling facility provides the computer simulations that test the potential atmospheric importance of AirUCI’s research findings. He investigates the importance to air pollution in the South Coast Air Basin of California of reactions of air and water molecules with particles that cling to buildings.
Dr. Dabdub is interested in the mathematical modeling of air pollution dynamics. His research is conducted in two areas: atmospheric sciences and computational sciences. Working in the area of atmospheric sciences, his work is aimed at the mathematical modeling of urban and global air pollution, understanding the dynamics of atmospheric aerosols, and global climate change.
Within the realm of computational sciences, Dr. Dabdub is interested in massively parallel computations, the numerical analysis of partial differential equations, and the development of problem solving environments. His current activities include a modeling study of Cl2 formation from aqueous NaCl particles; development of a semi-Lagrangian flux scheme for the solution of the aerosol condensation/evaporation equation; development of a two-level time-marching scheme using splines for solving the advection equation; and an investigation into the effect of alveolar volume and sequential filling on the diffusing capacity of the lungs. His work can be applied to foster a better understanding of air pollution and the dynamics of global climate change. 

Selected Honors and Awards: 
Henry Samueli School of Engineering Best Professor Award, 2007-2008
Pi Tau Sigma Honorary Professor Award , 2005
Gaspar de Portola International Fellowship, 2002
UCI Project Prometheus Teaching Award, 2001
National Science Foundation CAREER Award, 2000
W. E. Schiesser Distinguished Lecture, Lehigh University, 1999
William Corcoran Fellowship, 1990-1995
Tau Beta Pi National Engineering Honor Society, 1987
Phi Eta Sigma National Honor Society, 1986