Uncertainty in global CCN concentrations from uncertain aerosol nucleation and primary emission rates
305 citations recorded by the source corpus.
Abstract. The indirect effect of aerosols on climate is highly uncertain and limits our ability to assess anthropogenic climate change. The foundation of this uncertainty is uncertainty in the number of cloud condensation nuclei (CCN), which itself stems from uncertainty in aerosol nucleation, primary emission and growth rates. In this paper, we use a global general circulation model with aerosol microphysics to assess how the uncertainties in aerosol nucleation, emission and growth rates affect our prediction of CCN(0.2%) concentrations. Using several nucleation rate parameterizations that span six orders of magnitude of globally averaged nucleation rates, the tropospheric average CCN(0.2%) concentrations vary by 17% and the boundary layer average vary by 12%. This sensitivity of tropospheric average CCN(0.2%) to the nucleation parameterizations increases to 33% and 20% when the total primary emissions are reduced by a factor of 3 and the SOA condensation rates are increased by a factor of 3.5, respectively. These results show that it is necessary to better understand global nucleation rates when determining CCN concentrations. When primary emissions rates are varied by a factor of 3 while using a binary nucleation parameterization, tropospheric average CCN(0.2%) concentrations also vary by 17%, but boundary layer average vary by 40%. Using the fastest nucleation rate parameterization, these changes drop to 3% and 22%, respectively. These results show the importance of reducing uncertainties in primary emissions, which appear from these results to be somewhat more important for CCN than the much larger uncertainties in nucleation. These results also show that uncertainties in nucleation and primary emissions are more important when sufficient condensable material is available to grow them to CCN sizes. The percent change in CCN(0.2%) concentration between pre-industrial times and present day does not depend greatly on the nucleation rate parameterization used for our base case scenarios; however, because other factors, such as primary emissions and SOA, are uncertain in both time periods, this may be a coincidence.
Subfields: Atmospheric Science, Global and Planetary Change, Health, Toxicology and Mutagenesis
View Paper: https://www.semanticscholar.org/paper/ee9b04154de622b1e99b99ab478f0872e88eeb22
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Atmospheric Science
In Global and Planetary Change
In Health, Toxicology and Mutagenesis
Citations in the corpus
- Aerosol nucleation and its role for clouds and Earth's radiative forcing in the aerosol-climate model ECHAM5-HAM (2010, background): “Pierce and Adams(2009) demonstrated the impor- tance of reducing uncertainties in primary emissions for the investigation of aerosol nucleation on the global scale, as primary aerosol emissions bear strongly upon aerosol nucleation by removing nucleating and condensable molecules.”
- The magnitude and causes of uncertainty in global model simulations of cloud condensation nuclei (2013, result): “The relatively small uncertainty from nucleation is in agreement with earlier studies (Pierce and Adams, 2009).”
- JournalofGeophysicalResearch : Atmospheres Causes and importance of new particle formation in the present-day and preindustrial atmospheres (2017, unknown): “…atmosphere found that variations in the cosmic ray intensity typical of the solar cycle were very unlikely to produce significant variations in CCN concentrations [Pierce and Adams, 2009b; Snow-Kropla et al., 2011; Yu et al., 2012; Dunne et al., 2012; Kazil et al., 2012; Yu and Luo, 2014a].”
- Impact of nucleation on global CCN (2009, background): “Pierce and Adams (2009) found that boundary layer CCN (0.2”
- EUCAARI ion spectrometer measurements at 12 European sites – analysis of new particle formation events (2010, background): “Modeling studies indicate that nucleation may be a significant source of new CCN in the global atmosphere (e.g. Spracklen et al., 2008; Merikanto et al., 2009; Pierce and Adams, 2009).”
- Simulation of particle size distribution with a global aerosol model: contribution of nucleation to aerosol and CCN number concentrations (2009, methodology): “Pierce and Adams (2009) showed that uncertainties in nucleation, primary emissions and secondary organic aerosol (SOA) condensation may all influence predictions of CCN and emphasized the necessity to reduce the uncertainties in these processes in order to better understand the aerosol indirect…”
- Can cosmic rays affect cloud condensation nuclei by altering new particle formation rates? (2009, background): “Previous global evaluations have addressed the contribution of nucleation in general to CCN [e.g., Pierce and Adams, 2009; Spracklen et al., 2008] and the global contribution of cosmic rays to new-particle formation [Lucas and Akimoto, 2006], but not their subsequent growth to CCN.”
- Intercomparison and evaluation of global aerosol microphysical properties among AeroCom models of a range of complexity (2014, background): “Different assumptions for the size distribution of primary emitted particles have been shown to strongly influence simulated particle number concentrations (Pierce and Adams, 2009; Spracklen et al., 2010).”
- Cloud condensation nuclei production associated with atmospheric nucleation: a synthesis based on existing literature and new results (2012, background): “Primary particle emissions influence all the three processrelated quantities mentioned above, and especially their relative importance in atmospheric CCN production (Pierce and Adams, 2009; Spracklen et al., 2010, 2011a).”