| Literature DB >> 27790989 |
Hamish Gordon1, Kamalika Sengupta2, Alexandru Rap2, Jonathan Duplissy3, Carla Frege4, Christina Williamson5, Martin Heinritzi6, Mario Simon6, Chao Yan7, João Almeida8, Jasmin Tröstl4, Tuomo Nieminen9, Ismael K Ortega10, Robert Wagner7, Eimear M Dunne11, Alexey Adamov7, Antonio Amorim12, Anne-Kathrin Bernhammer13, Federico Bianchi14, Martin Breitenlechner15, Sophia Brilke6, Xuemeng Chen7, Jill S Craven16, Antonio Dias17, Sebastian Ehrhart8, Lukas Fischer15, Richard C Flagan16, Alessandro Franchin7, Claudia Fuchs4, Roberto Guida17, Jani Hakala7, Christopher R Hoyle18, Tuija Jokinen7, Heikki Junninen7, Juha Kangasluoma7, Jaeseok Kim19, Jasper Kirkby8, Manuel Krapf4, Andreas Kürten6, Ari Laaksonen20, Katrianne Lehtipalo14, Vladimir Makhmutov21, Serge Mathot17, Ugo Molteni4, Sarah A Monks22, Antti Onnela17, Otso Peräkylä7, Felix Piel6, Tuukka Petäjä7, Arnaud P Praplan7, Kirsty J Pringle2, Nigel A D Richards23, Matti P Rissanen7, Linda Rondo6, Nina Sarnela7, Siegfried Schobesberger7, Catherine E Scott2, John H Seinfeld16, Sangeeta Sharma24, Mikko Sipilä25, Gerhard Steiner26, Yuri Stozhkov21, Frank Stratmann27, Antonio Tomé12, Annele Virtanen28, Alexander Lucas Vogel17, Andrea C Wagner6, Paul E Wagner27, Ernest Weingartner4, Daniela Wimmer7, Paul M Winkler27, Penglin Ye29, Xuan Zhang16, Armin Hansel13, Josef Dommen4, Neil M Donahue29, Douglas R Worsnop30, Urs Baltensperger4, Markku Kulmala25, Joachim Curtius6, Kenneth S Carslaw31.
Abstract
The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentrations and aerosol-cloud radiative forcing over the industrial period. Model simulations show that the pure biogenic particle formation mechanism has a much larger relative effect on CCN concentrations in the preindustrial atmosphere than in the present atmosphere because of the lower aerosol concentrations. Consequently, preindustrial cloud albedo is increased more than under present day conditions, and therefore the cooling forcing of anthropogenic aerosols is reduced. The mechanism increases CCN concentrations by 20-100% over a large fraction of the preindustrial lower atmosphere, and the magnitude of annual global mean radiative forcing caused by changes of cloud albedo since 1750 is reduced by [Formula: see text] (27%) to [Formula: see text] Model uncertainties, relatively slow formation rates, and limited available ambient measurements make it difficult to establish the significance of a mechanism that has its dominant effect under preindustrial conditions. Our simulations predict more particle formation in the Amazon than is observed. However, the first observation of pure organic nucleation has now been reported for the free troposphere. Given the potentially significant effect on anthropogenic forcing, effort should be made to better understand such naturally driven aerosol processes.Entities:
Keywords: aerosol; biogenic; climate; forcing
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Year: 2016 PMID： 27790989 PMCID： PMC5087035 DOI： 10.1073/pnas.1602360113
Source DB: PubMed Journal: Proc Natl Acad Sci U S A ISSN： 0027-8424 Impact factor: 11.205