Black carbon (BC) in the atmosphere strongly absorbs solar radiation, while its warming effect on climate is poorly quantified. A key challenge is to accurately assess BC light absorption after being mixed with non-BC components in the atmosphere. However, field observations constantly stand in contrast to laboratory and modeling studies in BC light absorption estimation, reflecting the insufficient understanding of realistic BC complexity. Here, we report in-situ measurements of BC single-particle microphysics, e.g., size, coating amounts, density, and shape. We found that the large observation-modeling gap in light absorption of realistic BC-containing particles can be fully interpreted by neither standpoint proposed in previous literatures. Specifically, the observed particle-to-particle heterogeneities in size and coating, and the non-spherical BC shape explain the lower observed BC absorption by ~20% and ~30%, respectively; a remaining absorption gap for fully aged spherical BC-containing particles is necessarily related to the nonideal BC core position. Fully accounting for all the observed BC microphysics reduces the estimated global BC direct radiative forcing in climate models by up to 23%. Our study highlights that accurately assessing BC environmental and climate effects requires adequate representation of the real-world complexity of BC-containing particles in measurements and models.
 

黑碳气溶胶,吸光增强,微物理结构