Black carbon (BC) strongly absorbs solar radiation, contributing to global warming. Absorption enhancement of BC particles is difficult to quantify due to an inadequate representation of their complex morphology and mixing structures, as well as interaction with radiation. Here, we apply a 3D method accounting for detailed BC mixing structures to predict the absorption enhancement of individual BC particles (Eabs) and the total BC particle population (Eabs, bulk). The diverse range of mixing structures in individual BC particles leads to variable Eabs that could hardly be predicted by empirical approximations. We find that the volume proportion of the BC embedded in coating (F) determines Eabs when the particle to BC core diameter ratio (Dp/Dc) is larger than 2.0. Our findings reveal the potential mechanism behind the differences in observed and modeled Eabs, bulk. The framework builds a bridge connecting the microscopic mixing structure of individual BC particle with Eabs, bulk.
Bibliographical noteFunding Information:
We appreciate Peter Hyde’s comments and proofreading and Zeyun Shi’s advice on our python scripts. This work was supported by the National Natural Science Foundation of China (42075096 and 91844301), Zhejiang Provincial Natural Science Foundation of China (LZ19D050001), and Zhejiang Provincial Science and Technology Program in China (2021C01108).
© 2021. The Authors.
- black carbon
- individual particle analysis
- mixing state
- mixing structure
- optical absorption enhancement
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)