The impact of the atmospheric turbulence-development tendency on new particle formation: a common finding on three continents

Abstract

<jats:title>Abstract</jats:title> <jats:p>A new mechanism of new particle formation (NPF) is investigated using comprehensive measurements of aerosol physicochemical quantities and meteorological variables made in three continents, including Beijing, China, the Southern Great Plains site in the United States, and SMEAR II Station in Hyytiälä, Finland. Despite the considerably different emissions of chemical species among the sites, a common relationship was found between the characteristics of NPF and the stability intensity. The stability parameter (ζ = Z/L, where Z is the height above ground, and L is the Monin–Obukhov length) is found to play an important role, it drops significantly before NPF as the atmosphere becomes more unstable, which may serve as an indicator of nucleation bursts. As the atmosphere becomes unstable, the NPF duration is closely related to the tendency of turbulence development, which influences the evolution of the condensation sink. Presumably, the unstable atmosphere may dilute preexisting particles, effectively reducing the condensation sink especially at coarse mode to foster nucleation. This new mechanism is confirmed by model simulations using a molecular dynamic model that mimics the impact of turbulence development on nucleation by inducing and intensifying homogeneous nucleation events.</jats:p>

Vertical Profiles of Particle Number Size Distribution and Variation Characteristics at the Eastern Slope of the Tibetan Plateau

“…This phenomenon may be attributed to the sufficient vertical mixing within the PBL during the afternoon, which created regions of intense turbulence, further facilitating the formation of NPF events. The combination of favorable wind shear conditions and vertical turbulence mixing within the PBL contributes to the phenomenon of particle growth in specific regions and times [75]. In Figure 7b, another interesting phenomenon is shown at 17:00 LST on 12 July, where we observed a significant increase in the N 130-272 , particularly in the N 130-156 , within the PBL characterized by RH ranging between 67% and 73%.…”

“…Similarly, wind shear was observed between easterly and northerly winds at 650 m, with a N130-156-N226-272 value of 71.55 # cm −3 . Wind shear can enhance turbulence, promote particle collision and aggregation, and increase the likelihood of particle nucleation and growth processes, and lead to the occurrence of NPF, ultimately increasing the concentration of fine particles [75]. In Figure 7b, another interesting phenomenon is shown at 17:00 LST on 12 July, where we observed a significant increase in the N130-272, particularly in the N130-156, within the PBL characterized by RH ranging between 67% and 73%.…”

“…Similarly, wind shear was observed between easterly and northerly winds at 650 m, with a N 130-156 -N 226-272 value of 71.55 # cm −3 . Wind shear can enhance turbulence, promote particle collision and aggregation, and increase the likelihood of particle nucleation and growth processes, and lead to the occurrence of NPF, ultimately increasing the concentration of fine particles [75].…”

Vigorous New Particle Formation Above Polluted Boundary Layer in the North China Plain

“…To investigate the contributions of PBL vertical mixing to variations of aerosol number concentrations, we performed diagnostic analysis in WRF‐Chem modeling (Lai et al., 2022). Although small eddies that may impact local supersaturation are less resolved (Bigg, 1997; Nilsson et al., 2001; Wehner et al., 2010; Wu et al., 2021), given that this study mainly focuses on the influence from daytime NPF stratification, the SCM model is capable of capturing the dominant influence of convective PBL evolution on NPF (Shin & Dudhia, 2016).…”

A New Physical Mechanism of Rainfall Facilitation to New Particle Formation

“…Vertical mixing processes and PBL turbulence and dynamics were found to be the key factors impacting NPF events based on long‐term measurements of particle number and size distributions (N, n(a)) in European cities (Kulmala et al., 2023; Nilsson & Kulmala, 1998; Wehner et al., 2010). Recent studies have found that NPF events are facilitated by well‐developed turbulence on the three continents (Wu et al., 2021) and by a combination of precipitation, cold air, vertical transport of reactive gases from the ocean surface, and high actinic fluxes in a broken cloud field in a remote marine boundary layer (Zheng et al., 2021). Turbulence, precipitation, and cold air efficiently removed large particles, thus reducing the pre‐existing aerosol surface area and CS.…”