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Title: Radiative flux and forcing parameterization error in aerosol-free clear skies

This article reports on the accuracy in aerosol- and cloud-free conditions of the radiation parameterizations used in climate models. Accuracy is assessed relative to observationally validated reference models for fluxes under present-day conditions and forcing (flux changes) from quadrupled concentrations of carbon dioxide. Agreement among reference models is typically within 1 W/m 2, while parameterized calculations are roughly half as accurate in the longwave and even less accurate, and more variable, in the shortwave. Absorption of shortwave radiation is underestimated by most parameterizations in the present day and has relatively large errors in forcing. Error in present-day conditions is essentially unrelated to error in forcing calculations. Recent revisions to parameterizations have reduced error in most cases. As a result, a dependence on atmospheric conditions, including integrated water vapor, means that global estimates of parameterization error relevant for the radiative forcing of climate change will require much more ambitious calculations.
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ; ORCiD logo [6] ;  [2] ;  [7] ;  [8] ;  [9] ;  [7] ;  [10] ;  [11] ;  [12] ;  [13] ;  [11]
  1. Univ. of Colorado, Boulder, CO (United States); NOAA/Earth System Research Lab., Boulder, CO (United States)
  2. Atmospheric and Environmental Research, Lexington, MA (United States)
  3. NASA Goddard Space Flight Center, Greenbelt, MD (United States)
  4. Goddard Institute for Space Studies, New York, NY (United States)
  5. Univ. Pierre et Marie Curie, Paris (France); Korea Institute of Atmospheric Prediction Systems, Seoul (Korea)
  6. Univ. of Hamburg, Hamburg (Germany)
  7. Canadian Center Climate Modelling and Analysis, Environment Canada, Victoria, BC (Canada)
  8. Univ. Pierre et Marie Curie, Paris (France)
  9. Goddard Institute for Space Studies, New York, NY (United States); Trinnovim LLC, New York, NY (United States)
  10. Met Office, Exeter (United Kingdom)
  11. NOAA Geophysical Fluid Dynamics Lab., Princeton, NJ (United States)
  12. Centre National de Recherches Meteorologiques-GAME, Toulouse (France)
  13. Tokyo Univ. of Marine Science and Technology, Tokyo (Japan)
Publication Date:
Grant/Contract Number:
SC0012549; SC0012399
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 42; Journal Issue: 13; Journal ID: ISSN 0094-8276
American Geophysical Union
Research Org:
Univ. of Colorado, Boulder, CO (United States); Atmospheric and Environmental Research, Inc., Lexington, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; radiation; parameterization; radiative forcing
OSTI Identifier: