Limitations in the enhancement of visible light absorption due to mixing state

摘要: [1] Absorption by light-absorbing carbon (LAC) particles increases when the is mixed with other material, and this change affects climate forcing. We investigate increase theoretically over a realistic range of particle sizes. Perfect mixing at molecular level often overestimates absorption. Assuming that LAC coated concentric shell weakly absorbing we calculate absorption sizes identify regimes in which behaves similarly. provide fits to amplification five regions: (1) small cores (2) intermediate cores, both large shells; (3) (4) growing (5) shells. Amplification region 1 highest but physically implausible. 5 constant about 1.9 represents an asymptote for broad size distributions. Because aggregates amplified 1.3 above spherical particles, factor lost are coated, suggest aged aerosol 1.5 times greater than fresh aerosol. The rate acquire sufficient coating their original diameter 60% important determining total during atmospheric lifetimes. Fitted factors not very sensitive assumed refractive index can be used even simple models.