On the use of poorly soluble hygroscopic substances for modification of warm clouds and fogs

Romanov, N. P.; Дрофа, А. С.; Kim, N. S.; Savchenko, A. V.; Yaskevich, G. F.

doi:10.1134/s0001433806010075

Cited by 2 publications

(2 citation statements)

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“…As a result, rather paradoxical situation arises: it is a success to interpret the experimental dependencies of maximum droplet concentration on the cooling rate N max (U z ) within the frameworks of the theory of regular condensation but there is still no consistent description of the kinetics of the droplet size spectrum widening. Therefore, the mechanism of the rapid formation of widened spectra in cloud chambers remains unexplained that puts a question on the adequate modeling of influences by condensation nuclei at the initial stage of cloud formation [2,21,22].…”

Section: Discussionmentioning

confidence: 99%

Interrelation between variations of condensation nuclei concentration and cloud spectrum

Смирнов¹

2011

Russ. Meteorol. Hydrol.

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The characteristics are studied of warm cloud mediums (size spectra, concentration, etc.) formed in the cloud chamber of the volume of 3200 m 3 at adiabatic expansion of the humid air and at the variations of condensation nuclei concentration within the limits of 50-500 times from the initial one. To remove the nuclei, the volume electrostatic technique was used not requiring the ventilators. By means of the decrease in the cloud condensation nuclei concentration to the order of 100 cm -3 and less, it was succeeded for the first time to prevent the formation of clouds and fogs at adiabatic cooling of the humid air with equivalent speed of less than U z = 28 cm/s. At U z = 28-35 cm/s and nuclei concentration of 50-200 cm -3 , it becomes possible to simulate the fine-droplet hazes and fogs with monomodal spectra at average droplet diameter of 4-6 mm. At small and moderate rate U z = 11-100 cm/s and active nuclei concentration of 300-700 cm -3 , one can simulate the convective clouds with wide polymodal spectra. The potential of modern models of cloud spectra formation and the prospects of application of the technique of ion-stimulated variations of condensation nuclei concentration are discussed.

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Section: Discussionmentioning

confidence: 99%

Interrelation between variations of condensation nuclei concentration and cloud spectrum

Смирнов¹

2011

Russ. Meteorol. Hydrol.

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“…The first detailed description of its design and thermodynamic characteristics is given in (Romanov and Zhukov, 2000). This description is cited, in particular, by authors on the use of poorly soluble hygroscopic substances for modification of warm clouds and fogs (Romanov et al, 2006), (Drofa et al, 2010) and regularities of cloud microstructure formation and evolution (Romanov and Erankov, 2013). However, due to the inaccessibility of the above work (Romanov and Zhukov, 2000) for English-speaking readers the description below partially duplicates the content of this work.…”

Section: Lac Device Descriptionmentioning

confidence: 96%

Regularities of new particle formation and evolution of existing atmospheric aerosol particles in a large (3200 m<sup>3</sup>) isolated volume

Romanov

Paley

Andreev

et al. 2020

Preprint

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Abstract. The paper reports on an investigation of nanometre-sized new particles formation (NPF) in aerosol-free outdoor air. This phenomenon was observed after filling of Large Aerosol Chamber (LAC) RPA Typhoon with the volume of 3200 m3 with outdoor air, passed through HEPA 13 class filter (H13). During the summer-autumn period of 2018, even in the full darkness and in presence ionizing radiation only in the shape of secondary galactic cosmic rays, new particle formation with the particle size greater than 15 nm starts 0.5–1 hour after the end of LAC filling. During the 2018–2019 winter periods the NPF event was not observed once only. Approximately one day after NPF narrow bell-shaped spectra with number concentration up to 104 cm−3 and mass concentration up to 0.6 µg per m3 are formed. During the next five or more days, these size distributions evolve due to coagulation, while their asymptotic shape remains constant with relative breadth σc ≈ 0.28, and relative asymmetry ras ≈ 2 (ras = skewness/rb). The value ras ≈ 2 defines the analytical description of the size distribution as the gamma-distribution. During additional purification of newly formed particles with the inner H13 filter, aerosol particles concentration in LAC decreases down to a few particles per cm3. This concentration remained constant for more than a week. This demonstrates that new aerosol particles are formed by homogeneous gas-to-particle conversion of gaseous precursors, which passed through the external H13 filter. The mass concentration of newly formed particles depends on the concentration of precursors. It was found that after filling LAC with outdoor unfiltered air, approximately after 10 hours the left-hand side of aerosol particle size distribution below 15 nm disappears, and after several days there forms an asymptotic bell-shaped size spectrum with σc ≈ 0.4–0.5 and ras = 2–3. The modal diameter becomes about 150 nm after five days, while the size distribution greater than 200 nm remains unchanged. This allows concluding that aerosol particles greater than 200 nm have a life-time of more than five days, while particles smaller than 15 nm, not more than five hours. The observed regularities of NPF and pre-existing aerosol spectra evolution may contribute significantly to understanding the processes of the formation of atmospheric aerosols, which are responsible for cloud and precipitation formation. They also should be considered during the design of purification methods for facilities and living spaces. During the investigation of size distribution evolution of aerosol particles generated by the spraying of tap water, it was found that this aerosol particles size distribution transforms from a power law to a bell-shaped distribution in five days with σc ≈ 0.4 and ras ≈ 2. These results may be used for the development of aerosol evolution models.

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On the use of poorly soluble hygroscopic substances for modification of warm clouds and fogs

Cited by 2 publications

References 10 publications

Interrelation between variations of condensation nuclei concentration and cloud spectrum

Interrelation between variations of condensation nuclei concentration and cloud spectrum

Regularities of new particle formation and evolution of existing atmospheric aerosol particles in a large (3200 m<sup>3</sup>) isolated volume

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On the use of poorly soluble hygroscopic substances for modification of warm clouds and fogs

Cited by 2 publications

References 10 publications

Interrelation between variations of condensation nuclei concentration and cloud spectrum

Interrelation between variations of condensation nuclei concentration and cloud spectrum

Regularities of new particle formation and evolution of existing atmospheric aerosol particles in a large (3200 m&lt;sup&gt;3&lt;/sup&gt;) isolated volume

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Regularities of new particle formation and evolution of existing atmospheric aerosol particles in a large (3200 m<sup>3</sup>) isolated volume