Derivation and verification of an aerosol dynamics expression for the below-cloud scavenging process using the moment method

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

doi:10.1016/j.jaerosci.2009.11.006

Cited by 38 publications

(21 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, it was noted that due to the large number of parameters which play a role in the below-cloud scavenging processes (such as the above: effectiveness of the collisions, critical droplet velocity and distribution of rain droplets and aerosol particle sizes), the scavenging coefficient has a large degree of variability [19]. Therefore, the correct parametrization of its properties plays a relevant role in both climate models and models concerning the distribution of pollution [20].…”

Section: Introductionmentioning

confidence: 99%

Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions

Olszowski

2015

Ecological Chemistry and Engineering S

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions

Olszowski

2015

Ecological Chemistry and Engineering S

View full text Add to dashboard Cite

show abstract

“…Coarse particles (aerosol particle sizes are neither efficiently scavenged by Brownian diffusion nor by directional interception or inertial impaction, and this particle size range is called the "Greenfield gap" (Slinn, 1984). Recently, Bae et al (2010) added phoretic and electric charging effects to the collection efficiency assessment and found that the BWSCs increase by up to 20 times in the 0.2-3 μm particle size range. Wang et al (2014c) also improved the understanding of the electrical effects of the collision efficiency, which is also assumed to be a major source of uncertainty but is always ignored in theoretical estimations.…”

Section: Kdmentioning

confidence: 99%

“…The raindrop number size distribution and raindrop terminal velocity are both represented by empirical mathematical functions, and these factors are non-negligible. In order to minimize the computational burden, the calculation of BWSCs in most global and regional-scale models are expressed as the product of rain intensity multiplied by the collection efficiency, where the later is simplified as a constant or calculated based on the work of Slinn (Bae et al, 2010;Slinn, 1984). This simplification may undoubtedly bring into large uncertainties and make the simulated wet deposition within a factor of two ranges of the observations, which is significant larger compared with the 30% bias of the prediction of air pollutants evaluation (Vet et al, 2014;Zhu et al, 2018).…”

Section: Kdmentioning

confidence: 99%

“…Wet deposition is one of the dominant aerosol sinks on both global and regional scales (Min et al, 2005;Textor et al, 2006), and can be divided into in-cloud (particles are activated as cloud condensation nuclei and absorbed by cloud water) and belowcloud scavenging (aerosols and gas are captured by raindrops or snow particles after the hydrometeors leave the clouds) (Zhao et al, 2015). Previously, below-cloud scavenging is thought to be less important than in-cloud process and always simplified or even ignored in most global and regional chemical transport models (CTMs) (Tang et al, 2006;Bae et al, 2010;Barth et al, 2000;ENVIRON.Inc, 2005;Stier et al, 2005). This may be true in most clean atmosphere, e.g., developed country where air pollutants in the boundary layer were not sufficient.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multimethod determination of the below-cloud wet scavenging coefficients of aerosols in Beijing, China

Xu¹,

Ge²,

Chen³

et al. 2019

Preprint

View full text Add to dashboard Cite

Abstract. Wet scavenging is one of the most efficient processes that remove aerosols from the atmosphere. This process is not well constrained in chemical transport models (CTMs) due to a paucity of localized parameterization regarding below-cloud wet scavenging coefficient (BWSC). Here we conducted field measurements of the BWSC during the Atmospheric Pollution and Human Health-Beijing (APHH-Beijing) campaign of 2016. Notably, the observed BWSC values based on the updated aerosol mass balance agree well with another estimation technique by the updated aerosol mass balance, and they fall in a range of 10&#8722;5&#8201;s&#8722;1. The measurement in this winter campaign, combined with that in summer of 2014, supported an exponential power distribution of BWSCs with rainfall intensity. The observed parameters were also compared with both the theoretical calculations and modeling results. We found that the theoretical estimations can effectively characterize the observed BWSCs of aerosols with size smaller than 0.2 &#956;m and larger than 2.5 &#956;m. However, the theoretical estimations were one magnitude lower than observed BWSCs within 0.2&#8211;2.5&#8201;&#956;m, a domain size range of urban aerosols. Such an underestimation of BWSC through theoretical method has been confirmed not only in APHH-Beijing campaign but also in all the rainfall events in summer of 2014. Since the model calculations usually originated from the theoretical estimations with simplified scheme, the significant lower BWSC would well explain the underprediction of wet depositions in polluted regions as reported by the Model Inter-Comparison Study for Asia (MICS-Asia) and the global assessment of the Task Force on Hemispheric Transport of Atmospheric Pollutants (TF-HTAP). The findings highlighted that the wet deposition module in the CTMs requires improvement based on field measurement estimation to construct a more reasonable simulation scheme for BWSC, especially in polluted regions.

show abstract

“…Due to the considerable number of factors which play a role in the below-cloud processes, scavenging coefficients are characterized with a considerable degree of variability [18]. The application of adequate parameters for description of their characteristics poses a current problem in the descriptions of climate models and models that deal with the spatial distribution of pollutants [19]. Additionally, the scavenging coefficient Λ can seem complicated to an everyday reader, and it does not explain directly the scale of the process, since "the man in the street" could have problems interpreting the results of Λ reported here.…”

Section: Introductionmentioning

confidence: 99%

Comparison of PM10 washout on urban and rural areas

Olszowski

2017

Ecological Chemistry and Engineering S

View full text Add to dashboard Cite

This paper reports the results of research into the effectiveness of scavenging of PM10, resulting from the occurrence of solid and liquid hydrometeors. The measurement campaign was undertaken over 7 years and involved the registration of PM10 in areas which have different aerosanitary conditions (i.e. urban and undeveloped rural area). The analysis involved 426 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 indicated that in a urban location, the intensity of the local emission sources is a principal factor influencing the value of mass concentration changes and the effectiveness of the dust scavenging that accompanies a given type of precipitation. It was also noted that for the same intensity of precipitation, only the deposition of convective rainfall and long-term large-scale precipitation do not lead to statistically relevant differences in the value of mass concentrations of dust for both areas. It was indicated that during solid and liquid frontal precipitation of light intensity (< 0.5 mm·h -1 ), the effectiveness of PM10 removing is less in rural area. It was statistically proven that continuous precipitation of constant intensity and duration exceeding 2 hours has a similar effect of purifying the ambient air in both locations. The study revealed that short-term solid precipitation provides better characteristics of scavenging of PM10 compared with classic rainfall

show abstract

Derivation and verification of an aerosol dynamics expression for the below-cloud scavenging process using the moment method

Cited by 38 publications

References 44 publications

Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions

Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions

Multimethod determination of the below-cloud wet scavenging coefficients of aerosols in Beijing, China

Comparison of PM10 washout on urban and rural areas

Contact Info

Product

Resources

About

Derivation and verification of an aerosol dynamics expression for the below-cloud scavenging process using the moment method

Cited by 38 publications

References 44 publications

Concentration Changes Of PM10 Under Liquid Precipitation Conditions

Concentration Changes Of PM10 Under Liquid Precipitation Conditions

Multimethod determination of the below-cloud wet scavenging coefficients of aerosols in Beijing, China

Comparison of PM10 washout on urban and rural areas

Contact Info

Product

Resources

About

Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions

Concentration Changes Of PM₁₀ Under Liquid Precipitation Conditions