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Improving Our Fundamental Understanding of the Role of Aerosol-Cloud Interactions in the Climate System

 June 23-24, 2015; Irvine, CA
 Organized by John Seinfeld, Kimberly Prather, Ian Kraucunas, Alex Guenther and Edward Dunlea


This colloquium included scientists from a wide range of disciplines related to aerosols in the climate system to examine the questions of why has it been so difficult to constrain the role of aerosols in determining the Earth’s cloudiness, and what can be done to make better progress moving forward. With the release of the Intergovernmental Panel on Climate Change’s Fifth Assessment Report, there was an opportunity to look back across the history of all five IPCC reports and probe why the uncertainties related to clouds and aerosols remain the largest of any other.

The meeting brought an interdisciplinary perspective to the question of how to best make progress in constraining the overall uncertainty associated with aerosol-cloud interactions resulting in a thought-provoking discussion that examines the field as a whole and provides important details on the significant direction changes that need to be made.

Videos of the talks will be be available online as they are produced and approved by the speakers.


Tuesday, June 23, 2015
Session 1 – Welcome and Keynote

John Seinfeld, California Institute of Technology   
Welcome Introductions

Ken Carslaw, University of Leeds
Keynote address – Aerosol-cloud interactions in the climate system

Session 2 – Perspectives from the Modeling Community

Athanasios Nenes, Georgia Institute of Technology
Field and lab studies of cloud condensation nuclei, modeling parameterizations of cloud microphysical processes

Robert Wood (presenting on behalf of Steven Ghan, Pacific Northwest National Laboratory),   Aerosols and clouds in regional climate models

Chris Bretherton, University of Washington, Representations of clouds in climate models

Sonia Kreidenweis, Colorado State University, Cloud microphysics and parameterizing cloud condensation nuclei

Session 2 panel discussion moderated by John Seinfeld, California Institute of Technology

Session 3 – Perspectives from the Measurement Community

Hugh Coe, University of Manchester, Aircraft studies of aerosol and aerosol-cloud interactions

Robert Wood, University of Washington, Multisensor approaches to understanding connections between aerosols, shallow clouds and precipitation

Paul DeMott, Colorado State University, Field and laboratory studies on ice nuclei

Ralph Kahn, NASA, Remote Sensing of Aerosols From Satellites: Why has it been do difficult to quantify Aerosol-Cloud Interactions for climate assessment, and How can we make Progress?

Graeme Stephens, NASA Jet Propulsion Laboratory, Remote sensing of clouds and precipitation

Session 3 panel discussion moderated by Alex Guenther,  PNNL
Session 4 – Poster Session

Wednesday, June 24, 2015

Session 5 – Bringing It All Together

Daniel Rosenfeld, The Hebrew University of Jerusalem, Emerging capabilities of satellite retrievals of the fundamental properties required for disentangling aerosols and dynamical impacts on cloud radiative effects

Graham Feingold, NOAA ESRL, Large eddy simulation modeling of aerosols and clouds, interpretation of satellite and data

Phil Rasch, Pacific Northwest National Laboratory, Aerosols in the NCAR global climate model, geoengineering
Venkatachalam Ramaswamy, NOAA GFDL, Aerosols and clouds in global climate models, historical perspective on relevant IPCC chapters

Session 5 panel discussion moderated by Ian Kraucunas, PNNL

Session 6 – Looking Forward

Panel Discussion moderated by Kimberly Prather, University of California, San Diego
Barbara Finlayson-Pitts, University of California, Irvine
Mario Molina, University of California, San Diego
Veerabhadran Ramanathan, Scripps Institution of Oceanography
Joyce Penner, University of Michigan

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