Brown carbon: a significant atmospheric absorber of solar radiation?

Abstract. Several recent observational studies have shown organic carbon aerosols to be a significant source of absorption of solar radiation. The absorbing part of organic aerosols is referred to as "brown" carbon (BrC). Using a global chemical transport model and a radiative transfer model, we estimate for the first time the enhanced absorption of solar radiation due to BrC in a global model. The simulated wavelength dependence of aerosol absorption, as measured by the absorption Ångström exponent (AAE), increases from 0.9 for non-absorbing organic carbon to 1.2 (1.0) for strongly (moderately) absorbing BrC. The calculated AAE for the strongly absorbing BrC agrees with AERONET spectral observations at…

• NS
  National Science Foundation

  Award: DE-AC02-06CH11357
• UD
  U.S. Department of Energy

  Awards: AC02-06CH11357, contract DE-AC02-06CH11357, DE-AC02, 06CH11357, DE-AC02-06CH11357, DE-AC02-
• NE
  National Energy Research Scientific Computing Center
• AN
  Argonne National Laboratory

  Awards: DE-AC02, 06CH11357, AC02-06CH11357