Articles | Volume 15, issue 5
Atmos. Chem. Phys., 15, 2883–2888, 2015
https://doi.org/10.5194/acp-15-2883-2015
Atmos. Chem. Phys., 15, 2883–2888, 2015
https://doi.org/10.5194/acp-15-2883-2015

Research article 13 Mar 2015

Research article | 13 Mar 2015

Standard climate models radiation codes underestimate black carbon radiative forcing

G. Myhre and B. H. Samset G. Myhre and B. H. Samset
  • Center for International Climate and Environmental Research – Oslo (CICERO), Oslo, Norway

Abstract. Radiative forcing (RF) of black carbon (BC) in the atmosphere is estimated using radiative transfer codes of various complexities. Here we show that the two-stream radiative transfer codes used most in climate models give too strong forward scattering, leading to enhanced absorption at the surface and too weak absorption by BC in the atmosphere. Such calculations are found to underestimate the positive RF of BC by 10% for global mean, all sky conditions, relative to the more sophisticated multi-stream models. The underestimation occurs primarily for low surface albedo, even though BC is more efficient for absorption of solar radiation over high surface albedo.

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Short summary
Radiative forcing (RF) of black carbon (BC) in the atmosphere is estimated using radiative transfer codes of various complexities. Here we show that the two-stream radiative transfer codes used most in climate models give overly strong forward scattering, leading to enhanced absorption at the surface and overly weak absorption by BC. Such calculations are found to underestimate RF in all sky conditions by 10% for global mean, relative to the more sophisticated multi-stream model.
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