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

2012 ◽  
Vol 12 (1) ◽  
pp. 1553-1584
Author(s):  
R. W. Saunders ◽  
S. Dhomse ◽  
W. S. Tian ◽  
M. P. Chipperfield ◽  
J. M. C. Plane
Keyword(s):  
Sulphuric Acid ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Magnesium Silicate ◽  
Stratospheric Aerosol ◽  
Solution Viscosity ◽  
Time Resolved ◽  
Optical Extinction ◽  
Smoke Particles ◽  
Meteoric Smoke

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 H2SO4-H2O droplets in the global stratospheric aerosol (Junge) layer. This study describes a time-resolved spectroscopic analysis of the evolution of the ferric (Fe3+) ion originating from amorphous ferrous (Fe2+)-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 H2SO4 to the particle surfaces. Dissolution under stratospheric conditions should take less than a week, and is much faster than the dissolution of crystalline Fe2+ 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 t d−1. The model indicates that an uptake coefficient ≥0.01 is required to account for the observed two orders of magnitude depletion of H2SO4 vapour above 40 km.

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

2012 ◽  
Vol 12 (10) ◽  
pp. 4387-4398 ◽  
Author(s):  
R. W. Saunders ◽  
S. Dhomse ◽  
W. S. Tian ◽  
M. P. Chipperfield ◽  
J. M. C. Plane
Keyword(s):  
Sulphuric Acid ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Magnesium Silicate ◽  
Stratospheric Aerosol ◽  
Solution Viscosity ◽  
Time Resolved ◽  
Optical Extinction ◽  
Smoke Particles ◽  
Meteoric Smoke

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 H2SO4-H2O droplets in the global stratospheric aerosol (Junge) layer. This study describes a time-resolved spectroscopic analysis of the evolution of the ferric (Fe3+) ion originating from amorphous ferrous (Fe2+)-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 H2SO4 to the particle surfaces. Dissolution under stratospheric conditions should take less than a week, and is much faster than the dissolution of crystalline Fe2+ 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 H2SO4 vapour above 40 km.

Modelling the progression in the mix of particles within the Arctic stratospheric aerosol layer, including the seasonal source of meteoric smoke particles from the Arctic winter polar vortex 

2021 ◽  
Author(s):  
Kamalika Sengupta ◽  
Graham Mann ◽  
Ralf Weigel ◽  
James Brooke ◽  
Sandip Dhomse ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Particle Concentration ◽  
Aerosol Particles ◽  
Polar Vortex ◽  
Stratospheric Aerosol ◽  
The Arctic ◽  
Smoke Particles ◽  
Meteoric Smoke ◽  
Winter Time

<p>Meteoric smoke particles (MSPs) provide a steady source of condensation nuclei to the Arctic lower stratosphere, with heterogeneous nucleation to sulphuric acid aerosol particles.  Internally mixed meteoric-sulphuric particles likely also play a significant role in the formation of polar stratospheric clouds and thereby influence stratospheric ozone depletion chemistry, particularly in the quiescent stratosphere.</p><p>In several Arctic winter field campaigns (EUPLEX 2002/3, RECONCILE 2009/10, ESSenCe 2010/11),  in-situ stratospheric aerosol particle concentrations measurements were made from the high-altitude Geophysica aircraft, the COPAS instrument measuring total and refractory (non-volatile) particle concentrations at 20 km altitude (see Curtius et al., 2003; Weigel et al., 2014).  </p><p>These measurements are consistent with there being a substantial seasonal source of meteoric-sulphuric particles to the lower Arctic stratosphere, from each year’s influx of MSPs  within the winter-time Arctic polar vortex. In this study we investigate the effect of MSPs on the quiescent Junge layer particle concentration as the polar vortex builds up and after it dissipates. </p><p>We use the nudged configuration of the UM-UKCA stratosphere-troposphere composition-climate model to reproduce the vertical profile of stratospheric particles measured in-situ during the COPAS 2003 campaign. Our model simulates two types of stratospheric aerosol particles - pure sulphuric acid particles and sulphuric acid particles with a MSP-core. We show that the model is able to reproduce the vertical profile of aerosol particles observed during the COPAS measurements in winter 2003.</p><p>Our findings illustrate the influx of MSP and SO2 from higher altitudes through the polar vortex, the winter-time build-up of SO2 triggering homogeneous nucleation of pure sulphuric particles, also with the seasonal source of MSP-core sulphuric particles nucleated heterogeneously. We assess the effects of MSPs on the quiescent period particle concentration in the Arctic during winter through to spring.</p>

Numerical modeling of the natural and anthropogenic factors influence on the past and future changes in polar, mid-latitude and tropical ozone

2020 ◽  
Author(s):  
Sergei Smyshlyaev ◽  
Polina Blakitnaya ◽  
Maxim Motsakov ◽  
Vener Galin
Keyword(s):  
Solar Activity ◽  
Greenhouse Gases ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Stratospheric Ozone ◽  
Stratospheric Aerosol ◽  
Anthropogenic Factors ◽  
The Past ◽  
Ozone Depleting Substances ◽  
Natural And Anthropogenic Factors

<p>The INM RAS – RSHU chemistry-climate model of the lower and middle atmosphere is used to compare the role of natural and anthropogenic factors in the observed and expected variability of stratospheric ozone. Numerical experiments have been carried out on several scenarios of separate and combined effects of solar activity, stratospheric aerosol, sea surface temperature, greenhouse gases, and ozone-depleting substances emissions on ozone for the period from 1979 to 2050. Simulations for the past and present periods are compared to the results of ground-based and satellite observations, as well as MERRA and ERA-Interim re-analysis. Estimation of future ozone changes are based on different scenarios of changes in solar activity and emissions of ozone-depleting substances and greenhouse gases, as well as the possibility of large volcanic aerosol emissions at different periods of time.</p>

scholarly journals Distribution of meteoric smoke – sensitivity to microphysical properties and atmospheric conditions

2006 ◽  
Vol 6 (12) ◽  
pp. 4415-4426 ◽  
Author(s):  
L. Megner ◽  
M. Rapp ◽  
J. Gumbel
Keyword(s):  
Middle Atmosphere ◽  
Mass Density ◽  
Temporal Variations ◽  
Vertical Wind ◽  
Noctilucent Clouds ◽  
Atmospheric Conditions ◽  
Smoke Particles ◽  
Microphysical Properties ◽  
Meteoric Smoke ◽  
Atmospheric Phenomena

Abstract. Meteoroids entering the Earth's atmosphere experience strong deceleration and ablate, whereupon the resulting material is believed to re-condense to nanometre-size "smoke particles". These particles are thought to be of great importance for many middle atmosphere phenomena, such as noctilucent clouds, polar mesospheric summer echoes, metal layers, and heterogeneous chemistry. The properties and distribution of meteoric smoke depend on poorly known or highly variable factors such as the amount, composition and velocity of incoming meteoric material, the efficiency of coagulation, and the state and circulation of the atmosphere. This work uses a one-dimensional microphysical model to investigate the sensitivities of meteoric smoke properties to these poorly known or highly variable factors. The resulting uncertainty or variability of meteoric smoke quantities such as number density, mass density, and size distribution are determined. It is found that the two most important factors are the efficiency of the coagulation and background vertical wind. The seasonal variation of the vertical wind in the mesosphere implies strong global and temporal variations in the meteoric smoke distribution. This contrasts the simplistic picture of a homogeneous global meteoric smoke layer, which is currently assumed in many studies of middle atmospheric phenomena. In particular, our results suggest a very low number of nanometre-sized smoke particles at the summer mesopause where they are thought to serve as condensation nuclei for noctilucent clouds.

scholarly journals The global middle-atmosphere aerosol model MAECHAM5-SAM2: comparison with satellite and in-situ observations

2010 ◽  
Vol 3 (3) ◽  
pp. 1359-1421
Author(s):  
R. Hommel ◽  
C. Timmreck ◽  
H. F. Graf
Keyword(s):  
Sulphuric Acid ◽  
Middle Atmosphere ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Fine Mode ◽  
In Situ Observations ◽  
Polar Stratosphere

Abstract. In this paper we investigate results from a middle-atmosphere aerosol-climate model which has been developed to study the evolution of stratospheric aerosols. Here we focus on the stratospheric background period and evaluate several key quantities of the global dispersion of stratospheric aerosols and their precursors with observations and other model studies. It is shown that the model fairly well reproduces in situ observations of the aerosol size and number concentrations in the upper troposphere and lower stratosphere (UT/LS). Compared to measurements from the limb-sounding SAGE II satellite instrument, modelled integrated aerosol quantities are more biased the lower the moment of the aerosol population. Both findings are consistent with earlier work analysing the quality of SAGE II retrieved e.g. aerosol surface area densities from the volcanically unperturbed stratosphere (SPARC/ASAP, 2006; Thomason et al., 2008; Wurl et al., 2010). The model suggests that new particles are formed over large areas of the LS, albeit nucleation rates in the upper troposphere are at least one order of magnitude larger than those in the stratosphere. Hence, we suggest that both tropospheric sulphate aerosols and particles formed in situ in the LS are maintaining the stability of the stratospheric aerosol layer also in the absence of direct stratospheric emissions from volcanoes. Particle size distributions are clearly bimodal, except in the upper branches of the stratospheric aerosol layer where aerosols evaporate. Modelled concentrations of condensation nuclei (CN) are lesser than measured in regions of the aerosol layer where aerosol mixing ratios are largest, due to an overpredicted particle growth by coagulation. Transport regimes of tropical stratospheric aerosol have been identified from modelled aerosol mixing ratios and correspond to those deduced from satellite extinction measurements. We found that convective updraft in the Asian Monsoon region significantly contributes to both stratospheric aerosol load and size. The timing of formation and descend of layers of fine mode particles in the winter and spring polar stratosphere (CN layer) are reproduced by the model. Far above the tropopause where nucleation is inhibited due to with height increasing stratospheric temperatures, planetary wave mixing transports significant amounts of fine mode particles from the polar stratosphere to mid-latitudes. In those regions enhanced condensation rates of sulphuric acid vapour counteracts the evaporation of aerosols, hence prolonging the aerosol lifetime in the upper branches of the stratospheric aerosol layer. Measurements of the aerosol precursors SO2 and sulphuric acid vapour are fairly well reproduced by the model throughout the stratosphere.

scholarly journals Sensitivity of meteoric smoke distribution to microphysical properties and atmospheric conditions

2006 ◽  
Vol 6 (3) ◽  
pp. 5357-5386 ◽  
Author(s):  
L. Megner ◽  
M. Rapp ◽  
J. Gumbel
Keyword(s):  
Middle Atmosphere ◽  
Mass Density ◽  
Temporal Variations ◽  
Vertical Wind ◽  
Noctilucent Clouds ◽  
Atmospheric Conditions ◽  
Smoke Particles ◽  
Microphysical Properties ◽  
Meteoric Smoke ◽  
Atmospheric Phenomena

Abstract. Meteoroids entering the Earth's atmopsphere experience strong deceleration and ablate, whereupon the resulting material is believed to re-condense to nanometre-size "smoke particles". These particles are thought to be of great importance for many middle atmosphere phenomena, such as noctilucent clouds, polar mesospheric summer echoes, metal layers, and heterogeneous chemistry. The properties and distribution of meteoric smoke depend on poorly known or highly variable factors such as the amount, composition and velocity of incoming meteoric material, the efficiency of coagulation, and the state and circulation of the atmosphere. This work uses a one-dimensional microphysical model to investigate the sensitivities of meteoric smoke properties to these poorly known or highly variable factors. The resulting uncertainty or variability of meteoric smoke quantities such as number density, mass density, and size distribution are determined. It is found that the two most important factors are the efficiency of the coagulation and background vertical wind. The seasonal variation of the vertical wind in the mesosphere implies strong global and temporal variations in the meteoric smoke distribution. This contrasts the simplistic picture of a homogeneous global meteoric smoke layer, which is currently assumed in many studies of middle atmospheric phenomena. In particular, our results suggest a very low number of nanometre-sized smoke particles at the summer mesopause where they are thought to serve as condensation nuclei for noctilucent clouds.

scholarly journals Observations of NO in the upper mesosphere and lower thermosphere during ECOMA 2010

2012 ◽  
Vol 30 (11) ◽  
pp. 1611-1621 ◽  
Author(s):  
J. Hedin ◽  
M. Rapp ◽  
M. Khaplanov ◽  
J. Stegman ◽  
G. Witt
Keyword(s):  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Meteor Shower ◽  
The Other ◽  
Sounding Rocket ◽  
Northern Norway ◽  
Smoke Particles ◽  
Meteoric Smoke ◽  
Mesosphere And Lower Thermosphere ◽  
Main Instrument

Abstract. In December 2010 the last campaign of the German-Norwegian sounding rocket project ECOMA (Existence and Charge state Of Meteoric smoke particles in the middle Atmosphere) was conducted from Andøya Rocket Range in northern Norway (69° N, 16° E) in connection with the Geminid meteor shower. The main instrument on board the rocket payloads was the ECOMA detector for studying meteoric smoke particles (MSPs) by active photoionization and subsequent detection of the produced charges (particles and photoelectrons). In addition to photoionizing MSPs, the energy of the emitted photons from the ECOMA flash-lamp is high enough to also photoionize nitric oxide (NO). Thus, around the peak of the NO layer, at and above the main MSP layer, photoelectrons produced by the photoionization of NO are expected to contribute to, or even dominate above the main MSP-layer, the total measured photoelectron current. Among the other instruments on board was a set of two photometers to study the O2 (b1Σg+−X3Σg

scholarly journals The global middle-atmosphere aerosol model MAECHAM5-SAM2: comparison with satellite and in-situ observations

2011 ◽  
Vol 4 (3) ◽  
pp. 809-834 ◽  
Author(s):  
R. Hommel ◽  
C. Timmreck ◽  
H. F. Graf
Keyword(s):  
Sulphuric Acid ◽  
Middle Atmosphere ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Fine Mode ◽  
In Situ Observations ◽  
Polar Stratosphere

Abstract. In this paper we investigate results from a three-dimensional middle-atmosphere aerosol-climate model which has been developed to study the evolution of stratospheric aerosols. Here we focus on the stratospheric background period and evaluate several key quantities of the global distribution of stratospheric aerosols and their precursors with observations and other model studies. It is shown that the model fairly well reproduces in situ observations of the aerosol size and number concentrations in the upper troposphere and lower stratosphere (UT/LS). Compared to measurements from the limb-sounding SAGE II satellite instrument, modelled integrated aerosol quantities are more biased the lower the moment of the aerosol population is. Both findings are consistent with earlier work analysing the quality of SAGE II retrieved e.g. aerosol surface area densities in the volcanically unperturbed stratosphere (SPARC/ASAP, 2006; Thomason et al., 2008; Wurl et al., 2010). The model suggests that new particles are formed over large areas of the LS, albeit nucleation rates in the upper troposphere are at least one order of magnitude larger than those in the stratosphere. Hence, we suggest that both, tropospheric sulphate aerosols and particles formed in situ in the LS are maintaining the stability of the stratospheric aerosol layer in the absence of direct stratospheric emissions from volcanoes. Particle size distributions are clearly bimodal, except in the upper branches of the stratospheric aerosol layer where aerosols evaporate. Modelled concentrations of condensation nuclei (CN) are smaller than measured in regions of the aerosol layer where aerosol mixing ratios are largest. This points to an overestimated particle growth by coagulation. Transport regimes of tropical stratospheric aerosol have been identified from modelled aerosol mixing ratios and correspond to those deduced from satellite extinction measurements. We found that convective updraft in the Asian Monsoon region significantly contributes to both stratospheric aerosol load and size. The timing of formation and descend of layers of fine mode particles in the winter and spring polar stratosphere (CN layer) are well reproduced by the model. Where temperatures in the stratosphere increase with altitude, nucleation is unlikely to occur. Nevertheless, in these regions we find a significant concentration of fine mode aerosols. The place of origin of these particles is in the polar stratosphere. They are mixed into the mid-latitudes by planetary waves. There enhanced condensation rates of sulphuric acid vapour counteract evaporation and extend aerosol lifetime in the upper branches of the stratospheric aerosol layer. Measured aerosol precursors concentrations, SO2 and sulphuric acid vapour, are fairly well reproduced by the model throughout the stratosphere.

scholarly journals The role of carbonyl sulphide as a source of stratospheric sulphate aerosol and its impact on climate

2012 ◽  
Vol 12 (3) ◽  
pp. 1239-1253 ◽  
Author(s):  
C. Brühl ◽  
J. Lelieveld ◽  
P. J. Crutzen ◽  
H. Tost
Keyword(s):  
Radiative Forcing ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Ice Core ◽  
Stratospheric Aerosol ◽  
Quasi Biennial Oscillation ◽  
Direct Radiative Forcing ◽  
Upward Transport ◽  
Carbonyl Sulphide ◽  
Aerosol Module

Abstract. Globally, carbonyl sulphide (COS) is the most abundant sulphur gas in the atmosphere. Our chemistry-climate model (CCM) of the lower and middle atmosphere with aerosol module realistically simulates the background stratospheric sulphur cycle, as observed by satellites in volcanically quiescent periods. The model results indicate that upward transport of COS from the troposphere largely controls the sulphur budget and the aerosol loading of the background stratosphere. This differs from most previous studies which indicated that short-lived sulphur gases are also important. The model realistically simulates the modulation of the particulate and gaseous sulphur abundance in the stratosphere by the quasi-biennial oscillation (QBO). In the lowermost stratosphere organic carbon aerosol contributes significantly to extinction. Further, using a chemical radiative convective model and recent spectra, we compute that the direct radiative forcing efficiency by 1 kg of COS is 724 times that of 1 kg CO2. Considering an anthropogenic fraction of 30% (derived from ice core data), this translates into an overall direct radiative forcing by COS of 0.003 W m−2. The direct global warming potentials of COS over time horizons of 20 and 100 yr are GWP(20 yr) = 97 and GWP(100 yr) = 27, respectively (by mass). Furthermore, stratospheric aerosol particles produced by the photolysis of COS (chemical feedback) contribute to a negative direct solar radiative forcing, which in the CCM amounts to −0.007 W m−2 at the top of the atmosphere for the anthropogenic fraction, more than two times the direct warming forcing of COS. Considering that the lifetime of COS is twice that of stratospheric aerosols the warming and cooling tendencies approximately cancel.

scholarly journals The role of carbonyl sulphide as a source of stratospheric sulphate aerosol and its impact on climate

2011 ◽  
Vol 11 (7) ◽  
pp. 20823-20854 ◽  
Author(s):  
C. Brühl ◽  
J. Lelieveld ◽  
P. J. Crutzen ◽  
H. Tost
Keyword(s):  
Radiative Forcing ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Stratospheric Aerosol ◽  
Quasi Biennial Oscillation ◽  
Upward Transport ◽  
Global Warming Potentials ◽  
Carbonyl Sulphide ◽  
Aerosol Module

Abstract. Globally, carbonyl sulphide (COS) is the most abundant sulphur gas in the atmosphere. Our chemistry-climate model of the lower and middle atmosphere with aerosol module realistically simulates the background stratospheric sulphur cycle, as observed by satellites in volcanically quiescent periods. The model results indicate that upward transport of COS from the troposphere largely controls the sulphur budget and the aerosol loading of the background stratosphere. This differs from most previous studies which indicated that short-lived sulphur gases are also important. The model realistically simulates the modulation of the particulate and gaseous sulphur abundance in the stratosphere by the quasi-biennial oscillation (QBO). In the lowermost stratosphere organic carbon aerosol contributes significantly to extinction. Further, we compute that the radiative forcing efficiency by 1 kg of COS is 724 times that of 1 kg CO2, which translates into an overall radiative forcing by anthropogenic COS of 0.003 W m−2. The global warming potentials of COS over time horizons of 20 and 100 yr are GWP(20 yr) = 97 and GWP(100 yr) = 27, respectively (by mass). Furthermore, stratospheric aerosol particles produced by the photolysis of COS contribute to a negative radiative forcing, which amounts to −0.007 W m−2 at the top of the atmosphere for the anthropogenic fraction, more than two times the warming forcing of COS. Considering that the lifetime of COS is twice that of stratospheric aerosols the warming and cooling tendencies approximately cancel. If the forcing of the troposphere near the tropopause is considered, the cooling dominates.

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