Abstract
Abstract. Large uncertainties remain when estimating the warming effects of ambient black carbon (BC) aerosols on climate. One of the key challenges in modeling the radiative effects is predicting the BC light absorption enhancement, which is mainly determined by the mass ratio (MR) of non-BC coating material to BC in the population of BC-containing aerosols. For the same MR, recent research has found that the radiative absorption enhancements by BC are also controlled by its particle-to-particle heterogeneity. In this study, the BC mixing state index (χ) is developed to quantify the dispersion of ambient black carbon aerosol mixing states based on binary systems of BC and other non-black carbon components. We demonstrate that the BC light absorption enhancement increases with χ for the same MR, which indicates that χ can be employed as a factor to constrain the light absorption enhancement of ambient BC. Our framework can be further used in the model to study the radiative effects of black carbon on climate change.
Highlights
Black carbon (BC) aerosols absorb solar radiation, exerting warming effects on the earth’s energy system (Bond et al, 2006, 2013)
We demonstrate that the BC Eabs increases with χ for the same mass ratio (MR) based on the field measurement, which indicates that χ can be employed as a factor to constrain the Eabs properties of ambient BC
Previous studies find that the light absorption of ambient aerosols was mainly determined by the morphology of the BC core, the position of the BC core inside coating, the coating thickness, and the size distribution of the BC
Summary
Black carbon (BC) aerosols absorb solar radiation, exerting warming effects on the earth’s energy system (Bond et al, 2006, 2013). Some field measurement shows that the Eabs values of ambient BC aerosols are relatively small, with 1.06 at California (Cappa et al, 2012), 1.07 in South China (Lan et al, 2013), and 1.10 in Japan (Nakayama et al, 2014), while the measured Eabs of ambient BC reaches 1.59 during summer time in Beijing (Xie et al, 2019) Many factors, such as the morphology of the BC core, the position of BC core inside coating, the coating thickness, chemical properties of coating materials, and size distribution of the BC, influence the Eabs of ambient BC aerosols. We demonstrate that the BC Eabs increases with χ for the same MR based on the field measurement, which indicates that χ can be employed as a factor to constrain the Eabs properties of ambient BC
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
