Publication - Journal Article Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition

Proceedings of the National Academy of Sciences, vol. 117, iss. 10, pp. 5196-5203, 2020

Laura Fierce, Timothy B. Onasch, Christopher D. Cappa, Claudio Mazzoleni, Swarup China, Janarjan Bhandari, Paul Davidovits, D. Al Fischer, Taylor Helgestad, Andrew T. Lambe, Arthur J. Sedlacek, Geoffrey D. Smith, Lindsay Wolff

Significance Absorption by black carbon strongly affects regional and global climate. Yet, large discrepancies between standard model predictions and regionally specific observations—often with observed absorption lower than expected—raise questions about current understanding of black carbon absorption and its atmospheric impacts. Through a combination of measurement and modeling, our analysis resolves the discrepancy by showing that particular laboratory designs or atmospheric conditions engender distinct compositional heterogeneity among particles containing black carbon. Lower-than-expected absorption results largely from increased heterogeneity, although slightly lowered absorption occurs even in a purely homogeneous system. This work provides a framework that explains globally disparate observations and that can be used to improve estimates of black carbon’s global impact.