Interaction of Aerosol Particles and Clouds

Flossmann, Andrèa I.

doi:10.1175/1520-0469(1998)055<0879:ioapac>2.0.co;2

Cited by 46 publications

(39 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although during precipitation such a process is highly inhomogeneous spatially and the entrainment rate varies with time, it will be characterised here by average values for a typical extent of a rain event. Insight into the physics of entrainment is available from direct field measurements (Martin et al, 1994;Svenningsson et al, 1997;Snider and Brenguier, 2000), lidar data, high-resolution dynamic models, including large eddy simulations, and mesoscale models applied for simulation of precipitation (Rutledge and Hobbs, 1983;Niewiadomski, 1986;Tremblay, 1987;Houze, 1993;Flossmann, 1998;Zhang et al, 2004;Agusti-Panareda et al, 2005). Such studies show significant variability of the parameters describing entrainment, and the important roles of turbulence and convection.…”

Section: Model Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

et al. 2006

View full text Add to dashboard Cite

Abstract.Values of the scavenging coefficient determined from observations of ultrafine particles (with diameters in the range 10-510 nm) during rain events at a boreal forest site in Southern Finland between 1996 and 2001 were reported by Laakso et al. (2003a). The estimated range of the median values of the scavenging coefficient was [7×10 −6 −4×10 −5 ] s −1 , which is generally higher than model calculations based only on below-cloud processes (Brownian diffusion, interception, and typical phoretic and charge effects).In the present study, in order to interpret these observed data on scavenging coefficients from Laakso et al. (2003a), we use a model that includes below-cloud scavenging processes, mixing of ultrafine particles from the boundary layer (BL) into cloud, followed by cloud condensation nuclei activation and in-cloud removal by rainfall. The range of effective scavenging coefficient predicted by the new model, corresponding to wide ranges of values of its input parameters, are compared with observations. Results show that ultrafine particle removal by rain depends on aerosol size, rainfall intensity, mixing processes between BL and cloud elements, in-cloud scavenged fraction, in-cloud collection efficiency, and in-cloud coagulation with cloud droplets.The scavenging coefficients predicted by the new model are found to be significantly sensitive to the choice of representation of: (1) mixing processes; (2) raindrop size distribution; (3) phoretic effects in aerosol-raindrop collisions; and (4) cloud droplet activation. Implications for future studies of BL ultrafine particles scavenging are discussed.

show abstract

Section: Model Descriptionmentioning

confidence: 99%

“…The nature of precipitation is also important, since stratiform clouds tend to produce a less intense mixing, and are limited in vertical extent, while deep convection is very efficient in rapid mixing of tracers throughout troposphere (Flossmann, 1998;Crutzen and Lawrence, 2000;Lawrence et al, 2003).…”

Section: Mixing Of Ultrafine Particles Into Cloudmentioning

confidence: 99%

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

et al. 2006

View full text Add to dashboard Cite

show abstract

“…2 Design of the experiment to determine collection efficiency DESCAM (DEtailed SCavenging Model) is a bin-resolved cloud microphysics model (see Flossmann and Wobrock, 2010, Flossmann, 1998, or Quérel et al, 2014. It follows at each grid point number size distributions for liquid droplets, ice crystals and aerosol particles in the ambient air, as well the aerosol mass taken up into the drops and ice crystals.…”

Section: Introductionmentioning

confidence: 99%

An experiment to measure raindrop collection efficiencies: influence of rear capture

Quérel¹,

Lemaître

Monier

et al. 2014

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. In the case of severe accident with loss of containment in a nuclear plant, radionuclides are released into the atmosphere in the form of both gases and aerosol particles (Baklanov and Sørensen, 2001). The analysis of radioactive aerosol scavenged by rain after the Chernobyl accident highlights certain differences between the modelling studies and the environmental measurements. Part of these discrepancies can probably be attributed to uncertainties in the efficiencies used to calculate aerosol particle collection by raindrops, particularly drops with a diameter larger than one millimetre. In order to address the issue of these uncertainties, an experimental study was performed to close the gaps still existing for this key microphysical parameter. In this paper, attention is first focused on the efficiency with which aerosol particles in the accumulation mode are collected by raindrops with a diameter of 2 mm. The collection efficiencies measured for aerosol particle in the sub-micron range are quantitatively consistent with previous theoretical model developed by Beard (1974) and thus highlight the major role of rear capture in the submicron range.

show abstract

“…For instance, Kogan (1991), Ackerman et al (1995Ackerman et al ( , 2004, Flossmann (1998) and Khain et al (2001) resolved size spectrums of water condensates; Ghan et al (1997Ghan et al ( , 2001, Lohmann et al (1999), Khairoutdinov and Kogan (2000) and Chen and Liu (2004) calculated moments of cloud-and raindrops; and Lohmann and Roeckner (1996) and Menon et al (2002) used aerosol concentrations to parameterize cloud drop numbers. In these studies, aerosols act as CCNs to initialize the growth of cloud drops for the subsequent microphysical processes.…”

Section: Introductionmentioning

confidence: 99%

A modelling study of aerosol impacts on cloud microphysics and radiative properties

Cheng

Wang

Chen

2007

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

A warm cloud microphysical parameterization was incorporated into a regional model to study the sensitivity to aerosols of cloud-radiative properties and precipitation. Assuming a trimodal lognormal aerosol size distribution, the aerosol numbers were explicitly calculated from prognostic aerosol masses, considering advection, diffusion, and cloud and raindrop activation/deactivation processes. Clean continental, average continental and urban aerosols, each with different modal parameters, were used to serve as condensation nuclei (CCN) of cloud-and raindrops, whose activations depended on supersaturation and aerosol composition.Consistent with other studies, simulations conducted for a warm cloud system indicate that more aerosols result in more cloud water and more, but smaller, cloud drops, yielding increases in cloud albedo and decreases in surface precipitation. For example, the cloud drop effective radius decreased from ∼9 µm for clean continental aerosols to ∼5 and ∼2 µm, respectively, for average continental and urban aerosols, resulting in an increase in the respective cloud water path by ∼10% and ∼35% and cloud albedo by ∼6% and ∼12%. On the other hand, the accumulated precipitation decreased from 2.2 mm for clean continental aerosols to 1.9 and 1.2 mm, respectively, for average continental and urban aerosols. The presence of giant nuclei increased both the cloud drop effective radius and the precipitation, while the use of volumetric cloud drop radius tended to result in larger estimated cloud solar radiative forcing than the use of effective cloud drop radius.

show abstract

Interaction of Aerosol Particles and Clouds

Cited by 46 publications

References 23 publications

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

An experiment to measure raindrop collection efficiencies: influence of rear capture

A modelling study of aerosol impacts on cloud microphysics and radiative properties

Contact Info

Product

Resources

About