Abstract
Abstract. The number concentration of cloud droplets determines several climatically relevant cloud properties. A major cause for the high uncertainty in the indirect aerosol forcing is the availability of cloud condensation nuclei (CCN), which in turn is highly sensitive to atmospheric new particle formation. Here we present the effect of new particle formation on anthropogenic aerosol forcing in present-day (year 2000) and future (year 2100) conditions. The present-day total aerosol forcing is increased from −1.0 W m−2 to −1.6 W m−2 when nucleation is introduced into the model. Nucleation doubles the change in aerosol forcing between years 2000 and 2100, from +0.6 W m−2 to +1.4 W m−2. Two climate feedbacks are studied, resulting in additional negative forcings of −0.1 W m−2 (+10% DMS emissions in year 2100) and −0.5 W m−2 (+50% BVOC emissions in year 2100). With the total aerosol forcing diminishing in response to air pollution control measures taking effect, warming from increased greenhouse gas concentrations can potentially increase at a very rapid rate.
Highlights
Atmospheric new particle formation is a frequent phenomenon that enhances aerosol particle number concentrations almost everywhere in the troposphere (Kulmala et al, 2004; Spracklen et al, 2006, 2010; Yu et al, 2010)
We provide a quantification of the impact of aerosol nucleation on particle and cloud droplet number concentrations and anthropogenic aerosol forcing, accounting for the possible impact of increase in biogenic precursor emissions (BVOCs and oceanic dimethyl sulphide (DMS))
The upper panels show the results from simulations with nucleation turned off, indicating primary emission distribution, condensation of SO2 and biogenic volatile organic compounds (BVOCs) oxidation products make a minor contribution to CN
Summary
Atmospheric new particle formation is a frequent phenomenon that enhances aerosol particle number concentrations almost everywhere in the troposphere (Kulmala et al, 2004; Spracklen et al, 2006, 2010; Yu et al, 2010). While the initial nucleation occurs at about 1–2 nm of particle diameter, nucleated particles are able grow up to cloud condensations nuclei (CCN) sizes if sufficient amounts of condensable vapours are available (Lihavainen et al, 2003; Merikanto et al, 2009; Pierce and Adams, 2009; Yu and Luo, 2009). By this way, atmospheric new particle formation affects cloud droplet number concentrations (CDNC) (e.g., Kerminen et al, 2005; Makkonen et al, 2009; Merikanto et al, 2010).
Sign-in/Register to view highlights & summary 
Published Version (
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