The contribution of black carbon to global ice nucleating particle concentrations relevant to mixed-phase clouds.

Autor:	Schill GP; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371; gregory.schill@noaa.gov., DeMott PJ; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371., Emerson EW; Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872., Rauker AMC; Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872., Kodros JK; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371., Suski KJ; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371., Hill TCJ; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371., Levin EJT; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371., Pierce JR; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371., Farmer DK; Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872., Kreidenweis SM; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2020 Sep 15; Vol. 117 (37), pp. 22705-22711. Date of Electronic Publication: 2020 Aug 24.
DOI:	10.1073/pnas.2001674117
Abstrakt:	Black carbon (BC) aerosol plays an important role in the Earth's climate system because it absorbs solar radiation and therefore potentially warms the climate; however, BC can also act as a seed for cloud particles, which may offset much of its warming potential. If BC acts as an ice nucleating particle (INP), BC could affect the lifetime, albedo, and radiative properties of clouds containing both supercooled liquid water droplets and ice particles (mixed-phase clouds). Over 40% of global BC emissions are from biomass burning; however, the ability of biomass burning BC to act as an INP in mixed-phase cloud conditions is almost entirely unconstrained. To provide these observational constraints, we measured the contribution of BC to INP concentrations ([INP]) in real-world prescribed burns and wildfires. We found that BC contributes, at most, 10% to [INP] during these burns. From this, we developed a parameterization for biomass burning BC and combined it with a BC parameterization previously used for fossil fuel emissions. Applying these parameterizations to global model output, we find that the contribution of BC to potential [INP] relevant to mixed-phase clouds is ∼5% on a global average. Competing Interests: The authors declare no competing interest.
Databáze:	MEDLINE
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