Charged meteoric smoke as ice nuclei in the mesosphere: Part 1—A review of basic concepts

Gumbel, J.; Megner, Linda

doi:10.1016/j.jastp.2009.04.012

Cited by 58 publications

(55 citation statements)

References 74 publications

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“…The dotted line is the same calculation including the dipole interaction as well as the Coulomb interaction between the electron and the positively charged aerosol particles . The requirement for the neutralized particle to continue to growth is that it have the critical radius for condensation (∼0.5 nm) Gumbel and Megner, 2009). Figure 11 shows that positive nuclei can grow to critical size provided that there is a strong bite-out that reduces the electron density to about 100 cm −3 .…”

Section: Positive Charge On the Smallest Particlesmentioning

confidence: 99%

“…Recent modeling of meteoric smoke production and circulation shows that the smoke particles are carried away from the summer pole by circulation (Megner et al, 2006(Megner et al, , 2008Bardeen et al, 2008). Models for condensation require a minimum particle radius near 0.5 nm for typical conditions (Keesee, 1989;Megner et al, 2008;Gumbel and Megner, 2009;Winkler et al, 2008). Circulation models indicate that nanometer-sized meteoric condensation nuclei are likely to have summer densities of order 1 cm −3 which is far too low to account for the charged fraction of nanometer-sized particles observed by rocket-borne probes.…”

Section: Positive Charge On the Smallest Particlesmentioning

confidence: 99%

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Mass analysis of charged aerosol particles in NLC and PMSE during the ECOMA/MASS campaign

et al. 2009

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Abstract. MASS (Mesospheric Aerosol Sampling Spectrometer) is a multichannel mass spectrometer for charged aerosol particles, which was flown from the Andøya Rocket Range, Norway, through NLC and PMSE on 3 August 2007 and through PMSE on 6 August 2007. The eight-channel analyzers provided for the first time simultaneous measurements of the charge density residing on aerosol particles in four mass ranges, corresponding to ice particles with radii <0.5 nm (including ions), 0.5-1 nm, 1-2 nm, and >3 nm (approximately). Positive and negative particles were recorded on separate channels. Faraday rotation measurements provided electron density and a means of checking charge density measurements made by the spectrometer. Additional complementary measurements were made by rocket-borne dust impact detectors, electric field booms, a photometer and ground-based radar and lidar. The MASS data from the first flight showed negative charge number densities of 1500-3000 cm −3 for particles with radii >3 nm from 83-88 km approximately coincident with PMSE observed by the ALWIN radar and NLC observed by the ALOMAR lidar. For particles in the 1-2 nm range, number densities of positive and negative charge were similar in magnitude (∼2000 cm −3 ) and for smaller particles, 0.5-1 nm in radius, positive charge was dominant. The occurrence of positive charge on the aerosol particles of the smallest size and predominately negative charge on the particles of largest size suggests that nucleCorrespondence to: S. Knappmiller (knappmil@colorado.edu) ation occurs on positive condensation nuclei and is followed by collection of negative charge during subsequent growth to larger size. Faraday rotation measurements show a bite-out in electron density that increases the time for positive aerosol particles to be neutralized and charged negatively. The larger particles (>3 nm) are observed throughout the NLC region, 83-88 km, and the smaller particles are observed primarily at the high end of the range, 86-88 km. The second flight into PMSE alone at 84-88 km, found only small number densities (∼500 cm −3 ) of particles >3 nm in a narrow altitude range, 86.5-87.5 km. Both positive (∼2000 cm −3 ) and negative (∼4500 cm −3 ) particles with radii 1-2 nm were detected from 85-87.5 km.

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Section: Positive Charge On the Smallest Particlesmentioning

confidence: 99%

Section: Positive Charge On the Smallest Particlesmentioning

confidence: 99%

Mass analysis of charged aerosol particles in NLC and PMSE during the ECOMA/MASS campaign

et al. 2009

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“…MSPs are thought to participate in the nucleation of waterice clouds in the mesosphere (Rapp and Thomas, 2006;Gumbel and Megner, 2009), and also impact on trace vapours such as H 2 SO 4 and HNO 3 throughout the middle atmosphere (Turco et al, 1981;Prather and Rodriguez, 1988;Mills et al, 2005). After MSPs have been transported down from the mesosphere in the winter polar vortex , they are thought to be assimilated in liquid (supercooled) H 2 SO 4 -H 2 O droplets (typically 40-75 Wt % acid composition, radius >100 nm) in the stratospheric aerosol or Junge layer which is located between 15 and 30 km in altitude (Carslaw et al, 1997;Deshler, 2008).…”

Section: Introductionmentioning

confidence: 99%

Interactions of meteoric smoke particles with sulphuric acid in the Earth's stratosphere

et al. 2012

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Abstract. Nano-sized meteoric smoke particles (MSPs) with iron-magnesium silicate compositions, formed in the upper mesosphere as a result of meteoric ablation, may remove sulphuric acid from the gas-phase above 40 km and may also affect the composition and behaviour of supercooled H 2 SO 4 -H 2 O droplets in the global stratospheric aerosol (Junge) layer.This study describes a time-resolved spectroscopic analysis of the evolution of the ferric (Fe 3+ ) ion originating from amorphous ferrous (Fe 2+ )-based silicate powders dissolved in varying Wt % sulphuric acid (30-75 %) solutions over a temperature range of 223-295 K. Complete dissolution of the particles was observed under all conditions. The first-order rate coefficient for dissolution decreases at higher Wt % and lower temperature, which is consistent with the increased solution viscosity limiting diffusion of H 2 SO 4 to the particle surfaces. Dissolution under stratospheric conditions should take less than a week, and is much faster than the dissolution of crystalline Fe 2+ compounds.The chemistry climate model UMSLIMCAT (based on the UKMO Unified Model) was then used to study the transport of MSPs through the middle atmosphere. A series of model experiments were performed with different uptake coefficients. Setting the concentration of 1.5 nm radius MSPs at 80 km to 3000 cm −3 (based on rocket-borne charged particle measurements), the model matches the reported Wt % Fe values of 0.5-1.0 in Junge layer sulphate particles, and the MSP optical extinction between 40 and 75 km measured by a satellite-borne spectrometer, if the global meteoric input rate is about 20 tonnes per day. The model indicates that an uptake coefficient ≥0.01 is required to account for the observed two orders of magnitude depletion of H 2 SO 4 vapour above 40 km.

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“…Condensation nuclei are believed to significantly facilitate the formation of NLC particles, e.g. Gumbel and Megner (2009) ;Megner and Gumbel (2009). Because the particle cores are likely to be non-ice, the term "icy particles" instead of "ice particles" is used in the following.…”

Section: Introductionmentioning

confidence: 99%

Impacts of the January 2005 solar particle event on noctilucent clouds and water at the polar summer mesopause

et al. 2012

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Abstract. The response of noctilucent clouds to the solar particle event in January 2005 is investigated by means of icy particle and ion chemistry simulations. It is shown that the decreasing occurrence rate of noctilucent clouds derived from measurements of the SCIAMACHY/Envisat instrument can be reproduced by one-dimensional model simulations if temperature data from the MLS/Aura instrument are used. The model calculations indicate that the sublimation of noctilucent clouds leads to significant changes of the water distribution in the mesopause region. These model results are compared with H 2 O measurements from the MLS and the MIPAS/Envisat satellite instruments. The pronounced modelled water enhancement below the icy particle layer and its decrease during the SPE are not observed by the satellite instruments. At altitudes >85 km the satellite measurements show an increase of H 2 O during the SPE in qualitative agreement with the model predictions. The discrepancies between model H 2 O and observations at lower altitudes might be attributed to the one-dimensional model approach which in particular neglects inhomogeneities and horizontal transport processes. Additionally, it is revealed that the water depletion due to reactions of proton hydrates during the considered solar particle event has only a minor impact on the icy particles.

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Charged meteoric smoke as ice nuclei in the mesosphere: Part 1—A review of basic concepts

Cited by 58 publications

References 74 publications

Mass analysis of charged aerosol particles in NLC and PMSE during the ECOMA/MASS campaign

Mass analysis of charged aerosol particles in NLC and PMSE during the ECOMA/MASS campaign

Interactions of meteoric smoke particles with sulphuric acid in the Earth's stratosphere

Impacts of the January 2005 solar particle event on noctilucent clouds and water at the polar summer mesopause

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