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Title: The Global Aerosol Synthesis and Science Project (GASSP): Measurements and Modeling to Reduce Uncertainty

The largest uncertainty in the historical radiative forcing of climate is caused by changes in aerosol particles due to anthropogenic activity. Sophisticated aerosol microphysics processes have been included in many climate models in an effort to reduce the uncertainty. However, the models are very challenging to evaluate and constrain because they require extensive in situ measurements of the particle size distribution, number concentration, and chemical composition that are not available from global satellite observations. The Global Aerosol Synthesis and Science Project (GASSP) aims to improve the robustness of global aerosol models by combining new methodologies for quantifying model uncertainty, to create an extensive global dataset of aerosol in situ microphysical and chemical measurements, and to develop new ways to assess the uncertainty associated with comparing sparse point measurements with low-resolution models. GASSP has assembled over 45,000 hours of measurements from ships and aircraft as well as data from over 350 ground stations. The measurements have been harmonized into a standardized format that is easily used by modelers and nonspecialist users. Available measurements are extensive, but they are biased to polluted regions of the Northern Hemisphere, leaving large pristine regions and many continental areas poorly sampled. The aerosol radiative forcing uncertaintymore » can be reduced using a rigorous model–data synthesis approach. Nevertheless, our research highlights significant remaining challenges because of the difficulty of constraining many interwoven model uncertainties simultaneously. Although the physical realism of global aerosol models still needs to be improved, the uncertainty in aerosol radiative forcing will be reduced most effectively by systematically and rigorously constraining the models using extensive syntheses of measurements.« less
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  1. Univ. of Leeds (United Kingdom). School of Earth and Environment
  2. Univ. of Oxford (United Kingdom). Dept. of Physics
  3. Univ. of Manchester (United Kingdom). National Centre for Atmospheric Science, and School of Earth and Environmental Sciences
  4. Univ. of Leeds (United Kingdom). National Centre for Atmospheric Science, and the School of Earth and Environment
  5. Univ. of Hawaii, Honolulu, HI (United States)
  6. Leibniz Inst. for Tropospharenforschung, Leibniz (Germany)
  7. Environment and Climate Change Canada, Toronto, Ontario (Canada)
  8. Max Planck Inst. for Chemistry, Mainz (Germany)
  9. Paul Scherrer Inst. (PSI), Villigen (Switzerland); Centre for Ecology and Hydrology, Edinburgh (United Kingdom)
  10. National Inst. of Polar Research, Tachikawa, Tokyo (Japan)
  11. Meteorological Research Inst. (MRI), Tsukuba (Japan)
  12. National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.
  13. Georgia Inst. of Technology, Atlanta, GA (United States)
  14. NASA Langley Research Center, Hampton, VA (United States)
  15. The Cyprus Inst., Nicosia (Cyprus). Energy, Environment and Water Research Center
  16. Univ. of Wyoming, Laramie, WY (United States). Dept. of Atmospheric Science
  17. Stockholm Univ. (Sweden). Dept. of Meteorology
  18. National Oceanic and Atmospheric Administration (NOAA), Seattle, WA (United States). Pacific Marine Environmental Lab. (PMEL)
  19. Nanjing Univ. (China). School of Atmospheric Sciences
  20. Univ. of Colorado, Boulder, CO (United States)
  21. Univ. of California, Davis, CA (United States)
Publication Date:
Grant/Contract Number:
SC0007178; NE/J024252/1; NE/J022624/1; NE/J023515/1; NE/I020059/1; NE/I020148/1
Accepted Manuscript
Journal Name:
Bulletin of the American Meteorological Society
Additional Journal Information:
Journal Volume: 98; Journal Issue: 9; Journal ID: ISSN 0003-0007
American Meteorological Society
Research Org:
Univ. of California, Davis, CA (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF); Natural Environment Research Council (NERC); National Aeronautic and Space Administration (NASA)
Country of Publication:
United States
OSTI Identifier: