Gravito-photophoresis and aerosol stratification in the atmosphere

Cheremisin, A. A.; Vassilyev, Yu.V.; Horváth, H.

doi:10.1016/j.jaerosci.2005.02.003

Cited by 41 publications

(38 citation statements)

References 32 publications

(49 reference statements)

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“…Chemical processing and interaction with particles and trace gases in the troposphere lead to changes in the shape properties of the fire smoke particles. They are partly coated, embedded, or partially encapsulated after long-range transport (China et al, 2015). Smoke particles with a solid soot kernel and a spherical (liquid) sulfuric acid shell (Dahlkötter et al, 2014) would cause a depolarization ratio close to zero.…”

Section: The 21-23 August 2017 Smoke Event Over Central Europementioning

confidence: 99%

“…Fromm et al (2000Fromm et al ( , 2003 and Rosenfeld et al (2007) showed that large amounts of fire smoke can be lifted up to the tropopause within a short time period (less than 1 h) and can partly reach the lower stratosphere via the formation of pyrocumulonimbus clouds that are associated with strong updrafts with vertical wind velocities of 10-30 m s −1 (Fromm et al, 2010;Peterson et al, 2017). Self-lifting effects (Boers et al, 2010;Siddaway and Petelina, 2011;de Laat et al, 2012) and gravito-photophoresis forces (Rohatschek, 1996;Pueschel et al, 2000;Cheremisin et al, 2005;Renard et al, 2008) lead to a further ascent of the soot-containing layers.…”

Section: Introductionmentioning

confidence: 99%

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Extreme levels of Canadian wildfire smoke in the stratosphere over central Europe on 21–22 August 2017

et al. 2018

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Abstract. Light extinction coefficients of 500 Mm −1 , about 20 times higher than after the Pinatubo volcanic eruptions in 1991, were observed by European Aerosol Research Lidar Network (EARLINET) lidars in the stratosphere over central Europe on 21-22 August 2017. Pronounced smoke layers with a 1-2 km vertical extent were found 2-5 km above the local tropopause. Optically dense layers of Canadian wildfire smoke reached central Europe 10 days after their injection into the upper troposphere and lower stratosphere which was caused by rather strong pyrocumulonimbus activity over western Canada. The smoke-related aerosol optical thickness (AOT) identified by lidar was close to 1.0 at 532 nm over Leipzig during the noon hours on 22 August 2017. Smoke particles were found throughout the free troposphere (AOT of 0.3) and in the pronounced 2 km thick stratospheric smoke layer at an altitude of 14-16 km (AOT of 0.6). The lidar observations indicated peak mass concentrations of 70-100 µg m −3 in the stratosphere. In addition to the lidar profiles, we analyzed Moderate Resolution Imaging Spectroradiometer (MODIS) fire radiative power (FRP) over Canada, and the distribution of MODIS AOT and Ozone Monitoring Instrument (OMI) aerosol index across the North Atlantic. These instruments showed a similar pattern and a clear link between the western Canadian fires and the aerosol load over Europe. In this paper, we also present Aerosol Robotic Network (AERONET) sun photometer observations, compare photometer and lidar-derived AOT, and discuss an obvious bias (the smoke AOT is too low) in the photometer observations. Finally, we compare the strength of this recordbreaking smoke event (in terms of the particle extinction coefficient and AOT) with major and moderate volcanic events observed over the northern midlatitudes.

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Section: The 21-23 August 2017 Smoke Event Over Central Europementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Extreme levels of Canadian wildfire smoke in the stratosphere over central Europe on 21–22 August 2017

et al. 2018

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“…The resulting timeaverage force is called gravito-photophoretic (13). Such forces may alter the dynamics of natural aerosols in the upper atmosphere contributing to the formation of thin layers of aerosol observed in the mesosphere (12,15,16) and perhaps loft soot from the stratosphere to the mesosphere (14,16). Brownian motion randomizes a particle's orientation as the orienting torque becomes small compared to the particle's thermal energy.…”

Section: Photophoretic Forces On Aerosolsmentioning

confidence: 99%

“…Most research has focused on the possibility of injecting sulfur into the stratosphere (2,(4)(5)(6)(7)(8), although more elaborately engineered aerosols (9) and spacebased solar scattering systems have also been proposed (9,10). Here I examine the possibility that particles might be engineered to exploit photophoretic forces (11)(12)(13)(14)(15)(16), enabling the manipulation of particle distribution and radiative forcing in ways that could not be achieved with sulfate aerosol.…”

mentioning

confidence: 99%

Photophoretic levitation of engineered aerosols for geoengineering

Keith

2010

Proc. Natl. Acad. Sci. U.S.A.

127

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Aerosols could be injected into the upper atmosphere to engineer the climate by scattering incident sunlight so as to produce a cooling tendency that may mitigate the risks posed by the accumulation of greenhouse gases. Analysis of climate engineering has focused on sulfate aerosols. Here I examine the possibility that engineered nanoparticles could exploit photophoretic forces, enabling more control over particle distribution and lifetime than is possible with sulfates, perhaps allowing climate engineering to be accomplished with fewer side effects. The use of electrostatic or magnetic materials enables a class of photophoretic forces not found in nature. Photophoretic levitation could loft particles above the stratosphere, reducing their capacity to interfere with ozone chemistry; and, by increasing particle lifetimes, it would reduce the need for continual replenishment of the aerosol. Moreover, particles might be engineered to drift poleward enabling albedo modification to be tailored to counter polar warming while minimizing the impact on equatorial climates.

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“…It was shown that the altitude at which the photophoretic force balancing gravity corresponds to the altitude where observed aerosol layer existing in the atmosphere 2 . It may be considered as an evidence for a possible role of photophoretic forces in aerosol stratification in the atmosphere 3 . In previous experimental studies, it has been shown that the effect of sunlight on aerosol behaviour in the atmosphere could be significant and sometimes even stronger than the gravitational influence on individual aerosol particles 4 .…”

Section: Introductionmentioning

confidence: 99%

Parametric Analysis of Energy Absorption in Micro-particle Photophoresis in Absorbing Gaseous Media

Li¹,

Soong²,

Liu³

et al. 2010

DSJ

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The study deals with photophoresis of a spherical micro-particle suspended in absorbing gaseous media. Photophoretic motion of the particle stems from the asymmetric distribution of absorbed energy within the particle. By evaluating the so-called heat source function at various conditions, the study focuses on the effects of governing parameters on the energy distribution within the particle and their potential influences to the photophoresis. The results reveal that the increase in either particle size or absorptivity enhances the energy intensity on the illuminated (leading) side and tends to generate positive photophoresis. For a particle of low absorptivity, the energy distribution is dominated by particle refraction. Enhancing particle refractivity, the energy tends to be focused onto a certain spot area on the shaded (trailing) side and leads to a tendency of negative photophoresis. Increasing medium absorptivity significantly degrades the level of energy absorbed by the particle and in turn weakens the driving force of the particle photophoresis.

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Gravito-photophoresis and aerosol stratification in the atmosphere

Cited by 41 publications

References 32 publications

Extreme levels of Canadian wildfire smoke in the stratosphere over central Europe on 21–22 August 2017

Extreme levels of Canadian wildfire smoke in the stratosphere over central Europe on 21–22 August 2017

Photophoretic levitation of engineered aerosols for geoengineering

Parametric Analysis of Energy Absorption in Micro-particle Photophoresis in Absorbing Gaseous Media

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