Development and evaluation of an expression for polydisperse particle scavenging coefficient for the below-cloud scavenging as a function of rain intensity using the moment method

Bae, Sung‐Heui; Jung, Chang Hoon; Kim, Yong Pyo

doi:10.1016/j.jaerosci.2006.02.003

Cited by 28 publications

(35 citation statements)

References 16 publications

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“…These three parameters of the lognormal function are expressed as functions of rainfall intensity. In comparison with the exponential distribution, the gamma and lognormal distributions are usually better at representing the characteristics of observed raindrop size distributions at the small-raindrop end (e.g., Ulbrich, 1983;Willis, 1984;Feingold and Levin, 1986;Cerro et al, 1997;Mircea and Stefan, 1998;Mircea et al, 2000;de Wolf, 2001;Bringi et al, 2003;Brandes et al 2004;Bae et al, 2006;Henzing et al, 2006). This is due to the fact that the exponential function (see Eq.…”

Section: Raindrop Number Size Distribution N(d P )mentioning

confidence: 99%

Uncertainty assessment of current size-resolved parameterizations for below-cloud particle scavenging by rain

Wang¹,

2010

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Abstract. Current theoretical and empirical size-resolved parameterizations of the scavenging coefficient ( ), a parameter commonly used in aerosol transport models to describe below-cloud particle scavenging by rain, have been reviewed in detail and compared with available field and laboratory measurements. Use of different formulations for raindropparticle collection efficiency can cause uncertainties in sizeresolved values of one to two orders of magnitude for particles in the 0.01-3 µm diameter range. Use of different formulations of raindrop number size distribution can cause values to vary by a factor of 3 to 5 for all particle sizes. The uncertainty in caused by the use of different droplet terminal velocity formulations is generally small than a factor of 2. The combined uncertainty due to the use of different formulations of raindrop-particle collection efficiency, raindrop size spectrum, and raindrop terminal velocity in the current theoretical framework is not sufficient to explain the one to two order of magnitude under-prediction of for the theoretical calculations relative to the majority of field measurements. These large discrepancies are likely caused by additional known physical processes (i.e, turbulent transport and mixing, cloud and aerosol microphysics) that influence field data but that are not considered in current theoretical parameterizations. The predicted size-resolved particle concentrations using different theoretical parameterization can differ by up to a factor of 2 for particles smaller than 0.01 µm and by a factor of >10 for particles larger than 3 µm after 2-5 mm of rain. The predicted bulk mass and number concentrations (integrated over the particle size distribution) can differ by a factor of 2 between theoretical and empirical parameterizations after 2-5 mm of moderate intensity rainfall.

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Section: Raindrop Number Size Distribution N(d P )mentioning

confidence: 99%

Uncertainty assessment of current size-resolved parameterizations for below-cloud particle scavenging by rain

Wang¹,

2010

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“…According to [5], from the point of view of human health and the quality of the atmosphere, below-cloud scavenging seems to be more important due to the fact that particles of all types and sizes are deposed and transmitted to the ground-level zone in this 1 Department of Thermal Engineering and Industrial Facilities, Faculty of Mechanical Engineering, Opole University of Technology, ul. S. Mikołajczyka 5, Opole, Poland, phone +48 77 449 84 57, fax +48 77 449 99 24, email: t.olszowski@po.opole.pl process.…”

Section: Introductionmentioning

confidence: 99%

Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions

Olszowski

2015

Ecological Chemistry and Engineering S

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This study reports the results of field research into variability of the scavenging coefficient (Λ) of suspended dust comprising particles with aerodynamic diameters less than 10 mm. Registration of PM10 over 7 years in conditions of the occurrence of rainfall (convective light showers, large-scale precipitation and storms) was undertaken in an undeveloped rural area. The analysis involved 806 observations taken at constant time intervals of 0.5 hour. The measurements of the concentration of PM10 were performed by means of a reference method accompanied by concurrent registration of basic meteorological parameters. It was found that, for PM10, the scavenging efficiency is considerably influenced by rainfall intensity R and the type of precipitation. In the case of convective precipitation, data on Λ are only partially related to "classical approach" of rain scavenging. Within the range of comparable values of rainfall intensity, the type of wet deposition (except for storms) does not influence the effectiveness of scavenging PM10 from the ground-level zone. The large number of observations conducted in real-time conditions yielded a proposal of simple regression model, which can be deemed suitable for the description of variability Λ (DPM10), but only to a limited extent for large-scale precipitation. The collected results can be applied in air pollution dispersion models and deposition and were found to be generally representative for areas with similar climatic characteristics.

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“…A detailed description of the moment formula can be found in the literature (Jung et al, 2002;Bae et al, 2006). In this study, we did not consider the Cunningham slip correction factor.…”

Section: Minimum Collection Efficiency Diametermentioning

confidence: 99%

“…Rain intensity, however, can be easily measured. Thus, various scavenging coefficients, expressed as constants or functions of precipitation intensity, are still used in regional or mesoscale Lagrangian and Eulerian models to describe precipitation and the wet removal of pollutants (Seinfeld and Pandis 1998;Bae et al, 2006).…”

Section: Minimum Collection Efficiency Diametermentioning

confidence: 99%

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Minimum Collection Efficiency Particle Diameter during Precipitation as a Function of Rain Intensity

Jung

Lee

Bae

et al. 2013

Aerosol Air Qual. Res.

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This study found that the minimum collection efficiency particle diameter during precipitation is a function of rain intensity. The raindrop size distribution was parameterized with a log normal size distribution as a function of rain intensity, and the minimum collection efficiency and minimum collection efficiency diameter were obtained analytically.The results show that, during precipitation, both the minimum scavenging coefficient diameter and the minimum scavenging coefficient increase along with rain intensity. A comparison of the minimum collection efficiency diameters for various falling velocities reveals that there is not much of a difference in the diameters.Both the numerical and analytical results of this study agree well, without much loss of accuracy.

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Development and evaluation of an expression for polydisperse particle scavenging coefficient for the below-cloud scavenging as a function of rain intensity using the moment method

Cited by 28 publications

References 16 publications

Uncertainty assessment of current size-resolved parameterizations for below-cloud particle scavenging by rain

Uncertainty assessment of current size-resolved parameterizations for below-cloud particle scavenging by rain

Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions

Minimum Collection Efficiency Particle Diameter during Precipitation as a Function of Rain Intensity

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Development and evaluation of an expression for polydisperse particle scavenging coefficient for the below-cloud scavenging as a function of rain intensity using the moment method

Cited by 28 publications

References 16 publications

Uncertainty assessment of current size-resolved parameterizations for below-cloud particle scavenging by rain

Uncertainty assessment of current size-resolved parameterizations for below-cloud particle scavenging by rain

Concentration Changes Of PM10 Under Liquid Precipitation Conditions

Minimum Collection Efficiency Particle Diameter during Precipitation as a Function of Rain Intensity

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Product

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Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions