A parameterization of ion‐induced nucleation of sulphuric acid and water for atmospheric conditions

Modgil, Moninder Singh; Kumar, Sanjeev; Tripathi, Sachchida Nand; Lovejoy, Edward R.

doi:10.1029/2004jd005475

Cited by 53 publications

(63 citation statements)

References 16 publications

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“…However, in order for neutral nucleation to be initiated for the conditions considered here, the stabilizing effect of these unidentified species should be at least as strong as that of an ion core. Quantum calculations of the bonding energies of hydrated H 2 SO 4 monomers and dimers with ammonia and several common organic compounds (Nadykto and Yu, 2006) suggest that, while such species may enhance the overall stability of hydrated H 2 SO 4 dimers, the increase in stability is far less than that associated with an ion core. Accordingly, the substances commonly assumed in ternary homogeneous nucleation (THN) theories appear to be ineffective in initiating neutral nucleation under the circumstances of these case studies.…”

Section: Time Series Of the Concentrations Of Freshly Nucleated Partimentioning

confidence: 99%

Case studies of particle formation events observed in boreal forests: implications for nucleation mechanisms

Turco

2008

Atmos. Chem. Phys.

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Abstract. Aerosol nucleation events observed worldwide may have significant climatic and health implications. However, the specific nucleation mechanisms remain ambiguous. Here, we report case studies of eight nucleation events observed during an intensive field campaign at a boreal forest site (Hyytiälä, Finland) in spring 2005. The present analysis is based on comprehensive kinetic simulations using an ionmediated nucleation (IMN) model in which the key physical and chemical parameters are constrained by a variety of recent measurements. Out of the 22 days of the campaign on which nucleation events were observed, eight major events were selected for detailed analysis on the basis of indications that the observed air masses were relatively homogeneous. In most of these cases, reasonable agreement is found between IMN predictions and field data for a range of variables, including critical nucleation sizes, size-dependent overcharging ratios, and the concentrations of 1.8-3 nm stable clusters and 3-6 nm particles, and their diurnal variations. The possible reasons leading to substantial differences between observation and theory in some cases are also explored. Statistically, roughly 80% of the nucleation events recorded during the Hyytiälä campaign exhibited mean size-dependent particle overcharging ratios within the range of, or exceeding, those predicted by the IMN model, suggesting that ion nucleation processes were significant during these events. The nucleation rates calculated using the IMN modeling approach are contrasted with those predicted by other theories/models, and key differences between the results are discussed. In particular, it is concluded that the ion nucleation model originally developed by Lovejoy et al. (2004) significantly underCorrespondence to: F. Yu (yfq@asrc.cestm.albany.edu) predicts ion nucleation rates, and cannot explain the new observations from Hyytiälä regarding the electrical properties of nanoparticles. We also show that, for the well documented conditions of the Hyytiälä project, the binary and ternary homogeneous nucleation rates calculated using the most current theories would fall well below ∼10 −7 cm −3 s −1 , and thus would be negligible.

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Section: Time Series Of the Concentrations Of Freshly Nucleated Partimentioning

confidence: 99%

Case studies of particle formation events observed in boreal forests: implications for nucleation mechanisms

Turco

2008

Atmos. Chem. Phys.

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“…Depending on the nucleation mechanism or model of the nucleation mechanism, the predicted nucleation rates may differ by many orders of magnitude (Lucas and Akimoto, 2006;. Globally, Lucas and Akimoto (2006) showed that the maximum nucleation rates varied by five orders of magnitude between the Vehkamäki et al (2002) binary nucleation parameterization, ternary nucleation parameterization, and Modgil et al (2005) ion-induced nucleation parameterization.…”

Section: Introductionmentioning

confidence: 99%

Uncertainty in global CCN concentrations from uncertain aerosol nucleation and primary emission rates

2009

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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 Correspondence to: J. R. Pierce (jeffrey.robert.pierce@gmail.com) 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.

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“…The loss of supercritical particles smaller than the smallest represented particles due to coagulation among each other and with larger aerosol is then neglected, leading to an overestimation of particle formation rates. The resulting errors add to the intrinsic errors of aerosol nucleation parameterizations, which may exceed a factor of 2 Modgil et al, 2005). Figure 4a compares nucleation rates with formation rates of particles exceeding 2.5 nm in diameter, and illustrates the errors which may arise when the aerosol nucleation rate is used in lieu of the formation rate of larger particles: The nucleation rates markedly overestimate the >2.5 nm particle formation rates, in some cases by many orders of magnitude.…”

Section: Comparison Of Different Particle Formation Ratesmentioning

confidence: 99%

“…the determination of the surface tension of small molecular clusters of a given composition, and on the vapor pressures of the involved molecules above the corresponding bulk solution. Modgil et al (2005) parameterized nucleation rates that were calculated with a numerical aerosol model that resolves the initial steps of cluster formation molecule by molecule.…”

Section: Representing Secondary Aerosol Formation In Atmospheric Modelsmentioning

confidence: 99%

A semi-analytical method for calculating rates of new sulfate aerosol formation from the gas phase

Kazil

Lovejoy

2007

Atmos. Chem. Phys.

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Abstract. The formation of new aerosol from the gas phase is commonly represented in atmospheric modeling with parameterizations of the steady state nucleation rate. Present parameterizations are based on classical nucleation theory or on nucleation rates calculated with a numerical aerosol model. These parameterizations reproduce aerosol nucleation rates calculated with a numerical aerosol model only imprecisely. Additional errors can arise when the nucleation rate is used as a surrogate for the production rate of particles of a given size. We discuss these errors and present a method which allows a more precise calculation of steady state sulfate aerosol formation rates. The method is based on the semi-analytical solution of an aerosol system in steady state and on parameterized rate coefficients for H 2 SO 4 uptake and loss by sulfate aerosol particles, calculated from laboratory and theoretical thermodynamic data.

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A parameterization of ion‐induced nucleation of sulphuric acid and water for atmospheric conditions

Cited by 53 publications

References 16 publications

Case studies of particle formation events observed in boreal forests: implications for nucleation mechanisms

Case studies of particle formation events observed in boreal forests: implications for nucleation mechanisms

Uncertainty in global CCN concentrations from uncertain aerosol nucleation and primary emission rates

A semi-analytical method for calculating rates of new sulfate aerosol formation from the gas phase

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