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The chemistry influencing ODEs in the Polar Boundary Layer in spring: a model study

M. Piot1, R. von Glasow2, R. von Glasow1•
Heidelberg University1, University of East Anglia2
16 Apr 2008-Atmospheric Chemistry and Physics (Copernicus GmbH)-Vol. 8, Iss: 2, pp 7391-7453
TL;DR: In this article, sensitivity studies using the model MISTRA in the box-model mode on the influence of chemical species on these ozone depletion processes were performed in the polar boundary layer.
Abstract: . Near-total depletions of ozone have been observed in the Arctic spring since the mid 1980s. The autocatalytic cycles involving reactive halogens are now recognized to be of main importance for Ozone Depletion Events (ODEs) in the Polar Boundary Layer (PBL). We present sensitivity studies using the model MISTRA in the box-model mode on the influence of chemical species on these ozone depletion processes. In order to test the sensitivity of the chemistry under polar conditions, we compared base runs undergoing fluxes of either Br 2 , BrCl, or Cl 2 to induce ozone depletions, with similar runs including a modification of the chemical conditions. The role of HCHO, H 2 O 2 , DMS, Cl 2 , C 2 H 4 , C 2 H 6 , HONO, NO 2 , and RONO 2 was investigated. Cases with elevated mixing ratios of HCHO, H 2 O 2 , DMS, Cl 2 , and HONO induced a shift in bromine speciation from Br/BrO to HOBr/HBr, while high mixing ratios of C 2 H 6 induced a shift from HOBr/HBr to Br/BrO. Cases with elevated mixing ratios of HONO, NO 2 , and RONO 2 induced a shift to BrNO 2 /BrONO 2 . The shifts from Br/BrO to HOBr/HBr accelerated the aerosol debromination, but also increased the total amount of deposited bromine at the surface (mainly via increased deposition of HOBr). These shifts to HOBr/HBr also hindered the BrO self-reaction. In these cases, the ozone depletion was slowed down, where increases in H 2 O 2 and HONO had the greatest effect. The tests with increased mixing ratios of C 2 H 4 highlighted the decrease in HO x which reduced the production of HOBr from bromine radicals. In addition, the direct reaction of C 2 H 4 with bromine atoms led to less available reactive bromine. The aerosol debromination was therefore strongly reduced. Ozone levels were highly affected by the chemistry of C 2 H 4 . Cl 2 -induced ozone depletions were found unrealistic compared to field measurements due to the rapid production of CH 3 O 2 , HO x , and ROOH which rapidly convert reactive chlorine to HCl in a "chlorine counter-cycle". This counter-cycle efficiently reduces the concentration of reactive halogens in the boundary layer. Depending on the relative bromine and chlorine mixing ratios, the production of CH 3 O 2 , HO x , and ROOH from the counter-cycle can significantly affect the bromine chemistry. Therefore, the presence of both bromine and chlorine in the air may unexpectedly lead to a slow down in ozone destruction. For all NO y species studied (HONO, NO 2 , RONO 2 ) the chemistry is characterized by an increased bromine deposition on snow reducing the amount of reactive bromine in the air. Ozone is less depleted under conditions of high mixing ratios of NO x . The production of HNO 3 led to the acid displacement of HCl, and the release of chlorine out of salt aerosols (Cl 2 or BrCl) increased.

Summary (1 min read)

Jump to: [1 Introduction] – [5 Discussion of deposited bromine on snow] and [6 Conclusions]

1 Introduction

  • Since the first reports of dramatic decreases of ozone (so-called ODEs) in the Arctic during spring (Bottenheim et al., 1986; Oltmans and Komhyr, 1986; Barrie et al., 1988), intensive efforts have been made to better understand the processes involved10 in the observed ozone loss.
  • The names of their sensitivity runs include the20 source of halogens (Br2, BrCl, or Cl2) and additionally any change compared to the base run.
  • This paper does not intend to reproduce observed conditions, but rather to investigate the potential influence of several species on the halogen/ozone chemistry.
  • Br − concentrations, the chemistry is characterized only by the shift in bromine speciation and a resulting reduction of available highly reactive bromine radicals (not shown).

5 Discussion of deposited bromine on snow

  • The authors did not consider the recycling of bromine from the snow, as they focused on boundary layer chemical reactions influencing bromine/ozone.
  • Moreover, Piot and von Glasow (2007) showed that the deposition/re-emission process is essential for the timing of an ODE.
  • The model results highlighted here apply only for constant fluxes of halogens.
  • The different processes leading to the re-emission of deposited bromine on snow are not explicitly taken into account.
  • For results including recycling from the snow, the reader is re-15 ferred to Piot and von Glasow (2007).

6 Conclusions

  • The authors compared base runs undergoing Br2-, Cl2-, or BrCl-induced ODEs with similar runs including a modification in flux or mixing ratio of a species.
  • The main effect of this shift is rather the reduction in BrO self-reaction associated with the increased deposition on snow (mainly via HOBr deposition).
  • In that case, the activation of the chlorine counter-cycle unexpectedly leads to the reduction of reactive bromine and reduces the ozone depletion.
  • Less HOBr and more HBr clearly lead to the re-bromination of SSAs and the bromination of sulfate aerosols.

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The chemistry inuencing ODEs in the Polar Boundary
Layer in spring: a model study
M. Piot, R. von Glasow
To cite this version:
M. Piot, R. von Glasow. The chemistry inuencing ODEs in the Polar Boundary Layer in spring: a
model study. Atmospheric Chemistry and Physics Discussions, European Geosciences Union, 2008, 8
(2), pp.7391-7453. �hal-00304104�
ACPD
8, 7391–7453, 2008
The chemistry
influencing ODEs
M. Piot and R. von
Glasow
Title Page
Abstract Introduction
Conclusions References
Tables Figures
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Interactive Discussion
Atmos. Chem. Phys. Discuss., 8, 7391–7453, 2008
www.atmos-chem-phys-discuss.net/8/7391/2008/
© Author(s) 2008. This work is distributed under
the Creative Commons Attribution 3.0 License.
Atmospheric
Chemistry
and Physics
Discussions
The chemistry influencing ODEs in the
Polar Boundary Layer in spring: a model
study
M. Piot
1
and R. von Glasow
1,*
1
Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany
*
now at: School of Environmental Sciences, University of East Anglia, Norwich, UK
Received: 8 January 2008 – Accepted: 13 February 2008 – Published: 16 April 2008
Correspondence to: R. von Glasow (r.von-glasow@uea.ac.uk)
Published by Copernicus Publications on behalf of the European Geosciences Union.
7391
ACPD
8, 7391–7453, 2008
The chemistry
influencing ODEs
M. Piot and R. von
Glasow
Title Page
Abstract Introduction
Conclusions References
Tables Figures
◭ ◮
◭ ◮
Back Close
Full Screen / Esc
Printer-friendly Version
Interactive Discussion
Abstract
Near-total depletions of ozone have been observed in the Arctic spring since the mid
1980s. The autocatalytic cycles involving reactive halogens are now recognized to be
of main importance for Ozone Depletion Events (ODEs) in the Polar Boundary Layer
(PBL). We present sensitivity studies using the model MISTRA in the box-model mode
5
on the influence of chemical species on these ozone depletion processes. In order to
test the sensitivity of the chemistry under polar conditions, we compared base r uns un-
dergoing fluxes of either Br
2
, BrCl, or Cl
2
to induce ozone depletions, with similar runs
including a modification of the chemical conditions. The role of HCHO, H
2
O
2
, DMS,
Cl
2
, C
2
H
4
, C
2
H
6
, HONO, NO
2
, and RONO
2
was investigated. Cases with elevated
10
mixing ratios of HCHO, H
2
O
2
, DMS, Cl
2
, and HONO induced a shift in bromine speci-
ation from Br/BrO to HOBr/HBr, while high mixing ratios of C
2
H
6
induced a shift from
HOBr/HBr to Br/BrO. Cases with elevated mixing ratios of HONO, NO
2
, and RONO
2
induced a shift to BrNO
2
/BrONO
2
. The shifts from Br/BrO to HOBr/HBr accelerated the
aerosol debromination, but also increased the total amount of deposited bromine at the
15
surface (mainly via increased deposition of HOBr). These shifts to HOBr/HBr also hin-
dered the BrO self-reaction. In these cases, the ozone depletion was slowed down,
where increases in H
2
O
2
and HONO had the greatest effect. The tests with increased
mixing ratios of C
2
H
4
highlighted the decrease in HO
x
which reduced the production
of HOBr from bromine radicals. In addition, the direct reaction of C
2
H
4
with bromine
20
atoms led to less available reactive bromine. The aerosol debromination was there-
fore strongly reduced. Ozone levels were highly affected by the chemistry of C
2
H
4
.
Cl
2
-induced ozone depletions were found unrealistic compared to field measurements
due to the rapid production of CH
3
O
2
, HO
x
, and ROOH which rapidly convert reactive
chlorine to HCl in a “chlorine counter-cycle”. This counter-cycle efficiently reduces the
25
concentration of reactive halogens in the boundary layer. Depending on the relative
bromine and chlorine mixing ratios, the production of CH
3
O
2
, HO
x
, and ROOH from
the counter-cycle can significantly affect the bromine chemistry. Therefore, the pres-
7392
ACPD
8, 7391–7453, 2008
The chemistry
influencing ODEs
M. Piot and R. von
Glasow
Title Page
Abstract Introduction
Conclusions References
Tables Figures
◭ ◮
◭ ◮
Back Close
Full Screen / Esc
Printer-friendly Version
Interactive Discussion
ence of both bromine and chlorine in the air may unexpectedly lead to a slow down in
ozone destruction. For all NO
y
species studied (HONO, NO
2
, RONO
2
) the chemistry
is characterized by an increased bromine deposition on snow reducing the amount of
reactive bromine in the air. Ozone is less depleted under conditions of high mixing
ratios of NO
x
. The production of HNO
3
led to the acid displacement of HCl, and the
5
release of chlorine out of salt aerosols (Cl
2
or BrCl) increased.
1 Introduction
Since the first reports of dramatic decreases of ozone (so-called ODEs) in the Arc-
tic during spring (
Bottenheim et al., 1986; Oltmans and Komhyr, 1986; Barrie et al.,
1988), intensive efforts have been made to better understand the processes involved10
in the observed ozone loss. These events with low mixing ratios of ozone were cor-
related with high concentrations of filterable bromine (f-Br) (
Barrie et al., 1988, 1989;
Bottenheim et al., 1990). Later, BrO was observed with Long-Path DOAS (LP-DOAS,
see
Hausmann and Platt, 1994). Lehrer et al. (1997) showed a striking correlation be-
tween f-Br and BrO. During the ALERT2000 campaign, Br
2
and BrCl were measured
15
with mixing ratios as high as 30–35 pmol mol
−1
in April, while Cl
2
was not observed
above its detection limit of about 2 pmol mol
−1
(
Foster et al., 2001; Spicer et al., 2002).
Similarly, results from the chemical amplification method used by
Perner et al. (1999)
showed mixing ratios of ClO
x
(Cl+ClO) not exceeding 2 pmol mol
−1
in spr ing. Only
the measurements by Tuckermann et al. (1997) in Spitzbergen in 1995 indicated ClO20
mixing ratios up to 21 pmol mol
−1
. These values were not observed, however, in the
follow-up campaign in 1996. During the TOPSE aircraft program
Ridley et al. (2003)
showed that ozone depletions were actually widespread in the Arctic region. Indeed,
Zeng et al. (2003) estimated that about 20% of the Arctic regions were influenced by
persistent near-surface ODEs in spring. This is in accordance with remote sensing25
data from satellites measuring column BrO (Richter et al., 1998; Wagner and Platt,
1998). For more details on polar ODEs, see Simpson et al. (2007b).
7393
ACPD
8, 7391–7453, 2008
The chemistry
influencing ODEs
M. Piot and R. von
Glasow
Title Page
Abstract Introduction
Conclusions References
Tables Figures
◭ ◮
◭ ◮
Back Close
Full Screen / Esc
Printer-friendly Version
Interactive Discussion
Under ODE conditions halogen catalytic reaction cycles are responsible for the de-
pletion of O
3
. Halogens (X, Y=Br, Cl, I) directly destroy ozone via three main cycles
(see, e.g.,
von Glasow and Crutzen, 2007; Simpson et al., 2007b). Rate coefficients
between iodine and ozone are highest, but we do not focus on iodine chemistry in this
paper. Bromine is the most abundant and therefore, the most efficient halogen species5
for the ozone destruction:
Cycle I:
2(O
3
+ X −→ XO + O
2
) (1)
XO + XO −→ 2 X + O
2
(2)
−→ X
2
+ O
2
(3)
10
X
2
hν
−→ 2 X (4)
Net: 2 O
3
−→ 3 O
2
This cycle I is the fastest ozone-depleting reaction cycle for X=Br.
Cycle II:
XO + HO
2
−→ HOX + O
2
(5)
15
HOX
hν
−→ OH + X (6)
CO + OH
O
2
−→ HO
2
+ CO
2
(7)
Net: O
3
+ CO −→ O
2
+ CO
2
Reaction (
5) is very fast and represents a main pathway for the production of HOX.
Cycle III:
20
XO + YO −→ X + Y + O
2
(8)
−→ XY + O
2
(9)
−→ X + OYO (10)
Net: 2 O
3
−→ 3 O
2
7394
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References
More filters
Book•
Microphysics of Clouds and Precipitation

[...]

Hans R. Pruppacher, James D. Klett
31 Mar 1980
TL;DR: In this article, the authors focus on one major aspect of cloud microphysics, which involves the processes that lead to the formation of individual cloud and precipitation particles, and provide an account of the major characteristics of atmospheric aerosol particles.
Abstract: Cloud physics has achieved such a voluminous literature over the past few decades that a significant quantitative study of the entire field would prove unwieldy. This book concentrates on one major aspect: cloud microphysics, which involves the processes that lead to the formation of individual cloud and precipitation particles. Common practice has shown that one may distinguish among the following additional major aspects: cloud dynamics, which is concerned with the physics responsible for the macroscopic features of clouds; cloud electricity, which deals with the electrical structure of clouds and the electrification processes of cloud and precipitation particles; and cloud optics and radar meteorology, which describe the effects of electromagnetic waves interacting with clouds and precipitation. Another field intimately related to cloud physics is atmospheric chemistry, which involves the chemical composition of the atmosphere and the life cycle and characteristics of its gaseous and particulate constituents. In view of the natural interdependence of the various aspects of cloud physics, the subject of microphysics cannot be discussed very meaningfully out of context. Therefore, we have found it necessary to touch briefly upon a few simple and basic concepts of cloud dynamics and thermodynamics, and to provide an account of the major characteristics of atmospheric aerosol particles. We have also included a separate chapter on some of the effects of electric fields and charges on the precipitation-forming processes.

5,427 citations

"The chemistry influencing ODEs in t..." refers background in this paper

  • ...SSAs are produced by bursting bubbles at the sea surface (Woodcock, 1953; Pruppacher and Klett, 1997)....

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Journal Article•DOI•
Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate

[...]

Robert J. Charlson1, James E. Lovelock, Meinrat O. Andreae2, Stephen G. Warren1•
University of Washington1, Florida State University2
22 Apr 1987-Nature
TL;DR: The major source of cloud-condensation nuclei (CCN) over the oceans appears to be dimethylsulphide, which is produced by planktonic algae in sea water and oxidizes in the atmosphere to form a sulphate aerosol as mentioned in this paper.
Abstract: The major source of cloud-condensation nuclei (CCN) over the oceans appears to be dimethylsulphide, which is produced by planktonic algae in sea water and oxidizes in the atmosphere to form a sulphate aerosol Because the reflectance (albedo) of clouds (and thus the Earth's radiation budget) is sensitive to CCN density, biological regulation of the climate is possible through the effects of temperature and sunlight on phytoplankton population and dimethylsulphide production. To counteract the warming due to doubling of atmospheric CO2, an approximate doubling of CCN would be needed.

3,783 citations

Book•
Atmospheric Chemistry and Physics of Air Pollution

[...]

John H. Seinfeld
01 Jan 1986
TL;DR: The Gaussian Plume Equation and Air Quality Models Atmospheric Removal Processes and Residence Times Air Pollution Statistics Acid Rain Index (AIRI) as mentioned in this paper, which measures the amount of acid rain in the air.
Abstract: Air Pollutants Effects of Air Pollution Sources of Pollutants in Combustion Processes Gas-Phase Atmospheric Chemistry Aqueous-Phase Atmospheric Chemistry Mass Transfer Aspects of Atmospheric Chemistry Properties of Aerosols Dynamics of Single Aerosol Particles Thermodynamics of Aerosols and Nucleation Theory Dynamics of Aerosol Population Air Pollution Meteorology Micrometeorology Atmospheric Diffusion Theories The Gaussian Plume Equation The Atmospheric Diffusion Equation and Air Quality Models Atmospheric Removal Processes and Residence Times Air Pollution Statistics Acid Rain Index.

2,708 citations

"The chemistry influencing ODEs in t..." refers background in this paper

  • ...For a more thorough discussion please refer to, e.g., Seinfeld and Pandis (1998) or Finlayson-Pitts and Pitts (1999)....

    [...]

Book•
Chemistry of the Upper and Lower Atmosphere: Theory, Experiments, and Applications

[...]

Barbara J. Finlayson-Pitts, James N. Pitts
24 Nov 1999
TL;DR: A detailed overview of the chemistry of Polluted and Remote Atmospheres can be found in this paper, where the OZIPR model is used to simulate the formation of gases and particles in the Troposphere.
Abstract: Overview of the Chemistry of Polluted and Remote Atmospheres. The Atmospheric System. Spectroscopy and Photochemistry: Fundamentals. Photochemistry of Important Atmospheric Species. Kinetics and Atmospheric Chemistry. Rates and Mechanisms of Gas-Phase Reactions in Irradiated Organic-NOx-Air Mixtures. Chemistry of Inorganic Nitrogen Compounds. Acid Deposition: Formation and Fates of Inorganic and Organic Acids in the Troposphere. Particles in the Troposphere. Airborne Polycyclic Aromatic Hydrocarbons and Their Derivatives: Atmospheric Chemistry and Toxicological Implications. Analytical Methods and Typical Atmospheric Concentrations for Gases and Particles. Homogeneous and Heterogeneous Chemistry in the Stratosphere. Scientific Basis for Control of Halogenated Organics. Global Tropospheric Chemistry and Climate Change. Indoor Air Pollution: Sources, Levels, Chemistry, and Fates. Applications of Atmospheric Chemistry: Air Pollution Control Strategies and Risk Assessments for Tropospheric Ozone and Associated Photochemical Oxidants, Acids, Particles, and Hazardous Air Pollutants. Appendix I: Enthalpies of Formation of Some Gaseous Molecules, Atoms, and Free Radicals at 298 K. Appendix II: Bond Dissociation Energies. Appendix III: Running the OZIPR Model. Appendix IV: Some Relevant Web Sites. Appendix V: Pressures and Temperatures for Standard Atmosphere. Appendix VI: Answers to Selected Problems. Subject Index.

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01 Jan 2000-Atmospheric Environment
TL;DR: In this article, it is recommended that standard O 3 models include in their chemical mechanisms the following reaction probability parameterizations for reactive uptake of gases by aqueous aerosols and clouds: γ HO 2 =0.2 (range 0.1-1) for HO 2 → 0.5 H 2 O 2, γ NO 2 =10 −4 (10 −6 −10 −3 ) for NO 2 → HNO 3, and γ N 2 O 5 → 2 H NO 3.

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Additional excerpts

  • ...…the following reactions may become important: Cl + CH4 O2−→ HCl + CH3O2 (27) CH3O2 + HO2 −→ ROOH + O2 (28) ROOH + Cl −→ HCl + CH3O2 (29) ClO + CH3O2 −→ Cl + HCHO + HO2 (30)20 Cl + HCHO O2−→ HCl + HO2 + CO (31) where ROOH is a hydroperoxide (see, e.g., Jacob, 2000; Frey et al., 2006) with R=CnH2n+1....

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Frequently Asked Questions (18)
Q1. How many sulfate aerosols are produced in the box model?

The model includes 169 gas phase reactions (H-O-S-C-N-Br-Cl), as well as 150 aqueous phase reactions, 60 phase exchange reactions, 13 heterogeneous reactions and 21 equilibria for both sulfate and sea salt aerosols. 

The chemistry influencing ODEs in the Polar Boundary Layer in spring: a model study M. Piot, R. von Glasow 

H2O2 has a significant impact on the lifetime of trace gases as it constitutes a large potential source for gas phase oxidants (HOx) which contribute to the atmospheric oxidizing capacity. 

The primary effect of high concentrations of DMS on the ozone/halogen chemistry isthrough Reaction (25): BrO oxidizes DMS and produces 

Bottenheim et al. (2002a) measured atmospheric mixing ratios as high as 100 pmol mol −1 in early spring with a slow decrease with season. 

In that case, the activation of the chlorine counter-cycle unexpectedly leads to the reduction of reactive bromine and reduces the ozone depletion. 

Zeng et al. (2003) estimated that about 20% of the Arctic regions were influenced by persistent near-surface ODEs in spring. 

20Among HONO, NO2 and RONO2, HONO was found the most important species affecting the bromine/ozone chemistry due to the production of both highly reactive OH and NO. 

The removal of OH radicals from the atmo-5sphere by C2H6 (Reaction 36) is an important pathway reducing the concentration of HOx (Fig. 13c and d) as well as HCHO (Fig. 13e). 

This H2O2 flux induces gas phase mixing ratios three to four times higher than observations in the Arctic spring (de Serves, 1994). 

For all three nitrogencontaining species, the authors noted an acid displacement in SSAs from HNO3 to HCl and the increased release of chlorine compared to bromine out of SSAs. 

Br − is liberated in both cases via the bromine explosion cycle (Fig. 3c) and less reactive bromine is mostly10recycled via reaction in acidic sulfate aerosols (not shown). 

HCl reaches a maximum of 16 pmol mol −1 at the end of the model run (Fig. 14l) and SSA chloride displays a net decrease over the model run (not shown). 

The chemistryinfluencing ODEsM. Piot and R. vonGlasowTitle PageAbstract IntroductionConclusions ReferencesTables Figures◭ ◮◭ ◮Back CloseFull Screen / EscPrinter-friendly VersionInteractive DiscussionHowever, the main effect of this shift is rather the reduction in BrO self-reaction associated with the increased deposition on snow (mainly via HOBr deposition). 

These sensitivity studies show that higher fluxes of HCHO possibly causing the observed gas phase concentrations are required to significantly impact the ozone chemistry. 

Note that Br − in SSA increases during the last simulated day in the base run due to insufficient HOBr in the aqueous phase (see solid black line, Fig. 4d). 

As highlighted in this section, a higher flux of chlorine radicals induces an even stronger “chlorine counter-cycle”, shifting chlorine to HCl. 

Piot and von Glasow (2007) modeled meteorological and chemical processes that may influence the occurrence of an ODE with the snow surface acting as an efficient recycling surface.