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Steven Ghan

Earth Systems Analysis & Modeling
Laboratory Fellow
Pacific Northwest National Laboratory
PO Box 999
MSIN: K9-30
Richland, WA 99352


Dr. Steve Ghan is a climate scientist in the Atmospheric Sciences and Global Change Division at the Pacific Northwest National Laboratory. The mission of the division is to understand the atmospheric processes that drive regional and global earth systems, with a primary focus on climate, aerosol and cloud physics; global and regional scale modeling; integrated assessment; and complex regional meteorology and chemistry. Dr. Ghan's work involves a combination of development, evaluation, and application of parameterizations for climate models. He has focused on parameterizations that represent cloud-aerosol interactions and the subgrid influence of orography on atmospheric and land surface processes. He has worked closely with atmospheric chemists to produce self-consistent treatments of not only the influence of aerosols on clouds, but also the influence of clouds on aerosols. During 2007-2011 he led the Aerosol Climate Initiative for PNNL.

For the last fifteen years, Dr. Ghan's second research passion has been the representation of the subgrid influence of orography on atmospheric and land surface processes. By treating land as well as atmospheric processes in a consistent framework, the scheme produces high-resolution distributions of not only temperature and precipitation but also snow water, soil moisture, and runoff. His colleague, Dr. Ruby Leung, and he first developed the scheme in 1994, using a regional climate model as a testbed. They evaluated it by comparing with station measurements in a region with complex terrain, and then used it to simulate the impact of global warming on the climate of the Pacific Northwest. He subsequently applied the scheme to a global climate model, and in 2005 used it to produce global 5-km simulations of climate change for a 125-year IPCC scenario.

Research Interests

  • Cloud-aerosol interactions
  • Cloud microphysics parameterization
  • Aerosol-climate interactions
  • Chemistry-climate interactions
  • Global and regional climate modeling
  • Subgrid orography parameterization

Education and Credentials

  • Ph.D., Meteorology, Massachusetts Institute of Technology
  • M.S., Meteorology, Massachusetts Institute of Technology
  • B.S., in Atmospheric Science (cum laude), University of Washington

Affiliations and Professional Service

  • Member of American Geophysical Union
  • Editor, J. Geophysical Research - Atmospheres, 2007 - Present
  • Editor-in-Chief, J. Geophysical Research - Atmospheres, 2012 - Present

Awards and Recognitions

  • 2005-2009: Science Steering Committee, DOE Atmospheric Science Program
  • 2006-2011: Science Steering Committee, Community Climate System Model
  • 2007-2011: Led PNNL Aerosol Climate Initiative
  • 2009-Present: Science and Infrastructure Steering Committee, DOE Atmospheric Systems Research Program
  • 2009-Present: Co-chair, ASR Cloud-Aerosol-Precipitation Interactions Working Group
  • 2010-2012: Member, ARM Climate Research Facility Science Board
  • 2012-Present: Co-chair, Climate & Chemistry Working Group for the Community Earth System Model
  • 2012-Present: External Advisory Panel for National Science Foundation Center for Multiscale Modeling of Atmospheric Processes

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