Simulation of the diurnal variations of the oxygen isotope anomaly (&Delta;<sup>17</sup>O) of reactive atmospheric species

The isotope anomaly (&Delta;<sup>17</sup>O) of secondary atmospheric species such as nitrate (NO<sub>3</sub><sup>&minus;</sup>) or hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) has potential to provide useful constrains on their...

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Main Authors: J. Savarino, R. Sander, S. Morin
Format: Article
Language:English
Published: Copernicus Publications 2011-04-01
Series:Atmospheric Chemistry and Physics
Online Access:http://www.atmos-chem-phys.net/11/3653/2011/acp-11-3653-2011.pdf
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author J. Savarino
R. Sander
S. Morin
author_facet J. Savarino
R. Sander
S. Morin
author_sort J. Savarino
collection DOAJ
description The isotope anomaly (&Delta;<sup>17</sup>O) of secondary atmospheric species such as nitrate (NO<sub>3</sub><sup>&minus;</sup>) or hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) has potential to provide useful constrains on their formation pathways. Indeed, the &Delta;<sup>17</sup>O of their precursors (NO<sub>x</sub>, HO<sub>x</sub> etc.) differs and depends on their interactions with ozone, which is the main source of non-zero &Delta;<sup>17</sup>O in the atmosphere. Interpreting variations of &Delta;<sup>17</sup>O in secondary species requires an in-depth understanding of the &Delta;<sup>17</sup>O of their precursors taking into account non-linear chemical regimes operating under various environmental settings. <br><br> This article reviews and illustrates a series of basic concepts relevant to the propagation of the &Delta;<sup>17</sup>O of ozone to other reactive or secondary atmospheric species within a photochemical box model. We present results from numerical simulations carried out using the atmospheric chemistry box model CAABA/MECCA to explicitly compute the diurnal variations of the isotope anomaly of short-lived species such as NO<sub>x</sub> and HO<sub>x</sub>. Using a simplified but realistic tropospheric gas-phase chemistry mechanism, &Delta;<sup>17</sup>O was propagated from ozone to other species (NO, NO<sub>2</sub>, OH, HO<sub>2</sub>, RO<sub>2</sub>, NO<sub>3</sub>, N<sub>2</sub>O<sub>5</sub>, HONO, HNO<sub>3</sub>, HNO<sub>4</sub>, H<sub>2</sub>O<sub>2</sub>) according to the mass-balance equations, through the implementation of various sets of hypotheses pertaining to the transfer of &Delta;<sup>17</sup>O during chemical reactions. <br><br> The model results confirm that diurnal variations in &Delta;<sup>17</sup>O of NO<sub>x</sub> predicted by the photochemical steady-state relationship during the day match those from the explicit treatment, but not at night. Indeed, the &Delta;<sup>17</sup>O of NO<sub>x</sub> is "frozen" at night as soon as the photolytical lifetime of NO<sub>x</sub> drops below ca. 10 min. We introduce and quantify the diurnally-integrated isotopic signature (DIIS) of sources of atmospheric nitrate and H<sub>2</sub>O<sub>2</sub>, which is of particular relevance to larger-scale simulations of &Delta;<sup>17</sup>O where high computational costs cannot be afforded.
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spelling doaj.art-ee84c8452f604dbeaec956089c07767b2022-12-21T20:06:30ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242011-04-011183653367110.5194/acp-11-3653-2011Simulation of the diurnal variations of the oxygen isotope anomaly (&Delta;<sup>17</sup>O) of reactive atmospheric speciesJ. SavarinoR. SanderS. MorinThe isotope anomaly (&Delta;<sup>17</sup>O) of secondary atmospheric species such as nitrate (NO<sub>3</sub><sup>&minus;</sup>) or hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) has potential to provide useful constrains on their formation pathways. Indeed, the &Delta;<sup>17</sup>O of their precursors (NO<sub>x</sub>, HO<sub>x</sub> etc.) differs and depends on their interactions with ozone, which is the main source of non-zero &Delta;<sup>17</sup>O in the atmosphere. Interpreting variations of &Delta;<sup>17</sup>O in secondary species requires an in-depth understanding of the &Delta;<sup>17</sup>O of their precursors taking into account non-linear chemical regimes operating under various environmental settings. <br><br> This article reviews and illustrates a series of basic concepts relevant to the propagation of the &Delta;<sup>17</sup>O of ozone to other reactive or secondary atmospheric species within a photochemical box model. We present results from numerical simulations carried out using the atmospheric chemistry box model CAABA/MECCA to explicitly compute the diurnal variations of the isotope anomaly of short-lived species such as NO<sub>x</sub> and HO<sub>x</sub>. Using a simplified but realistic tropospheric gas-phase chemistry mechanism, &Delta;<sup>17</sup>O was propagated from ozone to other species (NO, NO<sub>2</sub>, OH, HO<sub>2</sub>, RO<sub>2</sub>, NO<sub>3</sub>, N<sub>2</sub>O<sub>5</sub>, HONO, HNO<sub>3</sub>, HNO<sub>4</sub>, H<sub>2</sub>O<sub>2</sub>) according to the mass-balance equations, through the implementation of various sets of hypotheses pertaining to the transfer of &Delta;<sup>17</sup>O during chemical reactions. <br><br> The model results confirm that diurnal variations in &Delta;<sup>17</sup>O of NO<sub>x</sub> predicted by the photochemical steady-state relationship during the day match those from the explicit treatment, but not at night. Indeed, the &Delta;<sup>17</sup>O of NO<sub>x</sub> is "frozen" at night as soon as the photolytical lifetime of NO<sub>x</sub> drops below ca. 10 min. We introduce and quantify the diurnally-integrated isotopic signature (DIIS) of sources of atmospheric nitrate and H<sub>2</sub>O<sub>2</sub>, which is of particular relevance to larger-scale simulations of &Delta;<sup>17</sup>O where high computational costs cannot be afforded.http://www.atmos-chem-phys.net/11/3653/2011/acp-11-3653-2011.pdf
spellingShingle J. Savarino
R. Sander
S. Morin
Simulation of the diurnal variations of the oxygen isotope anomaly (&Delta;<sup>17</sup>O) of reactive atmospheric species
Atmospheric Chemistry and Physics
title Simulation of the diurnal variations of the oxygen isotope anomaly (&Delta;<sup>17</sup>O) of reactive atmospheric species
title_full Simulation of the diurnal variations of the oxygen isotope anomaly (&Delta;<sup>17</sup>O) of reactive atmospheric species
title_fullStr Simulation of the diurnal variations of the oxygen isotope anomaly (&Delta;<sup>17</sup>O) of reactive atmospheric species
title_full_unstemmed Simulation of the diurnal variations of the oxygen isotope anomaly (&Delta;<sup>17</sup>O) of reactive atmospheric species
title_short Simulation of the diurnal variations of the oxygen isotope anomaly (&Delta;<sup>17</sup>O) of reactive atmospheric species
title_sort simulation of the diurnal variations of the oxygen isotope anomaly delta sup 17 sup o of reactive atmospheric species
url http://www.atmos-chem-phys.net/11/3653/2011/acp-11-3653-2011.pdf
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AT rsander simulationofthediurnalvariationsoftheoxygenisotopeanomalydeltasup17supoofreactiveatmosphericspecies
AT smorin simulationofthediurnalvariationsoftheoxygenisotopeanomalydeltasup17supoofreactiveatmosphericspecies