Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff
Iodine emissions from the dominant six macroalgal species in the coastal regions around Roscoff, France, have been modelled to support the Reactive Halogens in the Marine Boundary Layer Experiment (RHaMBLe) undertaken in September 2006. A two-dimensional model is used to explore the relationship bet...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2010-12-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/10/11823/2010/acp-10-11823-2010.pdf |
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| author | R. J. Leigh S. M. Ball J. Whitehead C. Leblanc A. J. L. Shillings A. S. Mahajan H. Oetjen J. D. Lee C. E. Jones J. R. Dorsey M. Gallagher R. L. Jones J. M. C. Plane P. Potin G. McFiggans |
| author_facet | R. J. Leigh S. M. Ball J. Whitehead C. Leblanc A. J. L. Shillings A. S. Mahajan H. Oetjen J. D. Lee C. E. Jones J. R. Dorsey M. Gallagher R. L. Jones J. M. C. Plane P. Potin G. McFiggans |
| author_sort | R. J. Leigh |
| collection | DOAJ |
| description | Iodine emissions from the dominant six macroalgal species in the coastal
regions around Roscoff, France, have been modelled to support the Reactive
Halogens in the Marine Boundary Layer Experiment (RHaMBLe) undertaken in
September 2006. A two-dimensional model is used to explore the relationship
between geographically resolved regional emissions (based on maps of seaweed
beds in the area and seaweed I<sub>2</sub> emission rates previously measured in
the laboratory) and in situ point and line measurements of I<sub>2</sub> performed
respectively by a broadband cavity ringdown spectroscopy (BBCRDS) instrument
sited on the shoreline and a long-path differential optical absorption
spectroscopy (LP-DOAS) instrument sampling over an extended light path to an
off-shore island. The modelled point and line I<sub>2</sub> concentrations compare
quantitatively with BBCRDS and LP-DOAS measurements, and provide a link
between emission fields and the different measurement geometries used to
quantify atmospheric I<sub>2</sub> concentrations during RHaMBLe. Total I<sub>2</sub>
emissions over the 100 km<sup>2</sup> region around Roscoff are calculated to be
1.7×10<sup>19</sup> molecules per second during the lowest tides.
<br><br>
During the night, the model replicates I<sub>2</sub> concentrations up to 50 pptv
measured along the LP-DOAS instrument's line of sight, and predicts spikes of
several hundred pptv in certain conditions. Point I<sub>2</sub> concentrations up
to 50 pptv are also calculated at the measurement site, in broad agreement
with the BBCRDS observations. Daytime measured concentrations of I<sub>2</sub> at
the site correlate with modelled production and transport processes. However
substantial recycling of the photodissociated I<sub>2</sub> is required for the
model to quantitatively match measured concentrations. This result
corroborates previous modelling of iodine and NO<sub>x</sub> chemistry in the
semi-polluted marine boundary layer which proposed a mechanism for recycling
I<sub>2</sub> via the formation, transport and subsequent reactions of the
IONO<sub>2</sub> reservoir compound.
<br><br>
The methodology presented in this paper provides a tool for linking spatially
distinct measurements to inhomogeneous and temporally varying emission
fields. |
| first_indexed | 2024-12-13T08:02:41Z |
| format | Article |
| id | doaj.art-ac6739c4bf8845e883dffcbd38ec2fb4 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-13T08:02:41Z |
| publishDate | 2010-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-ac6739c4bf8845e883dffcbd38ec2fb42022-12-21T23:54:24ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242010-12-011023118231183810.5194/acp-10-11823-2010Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around RoscoffR. J. Leigh0S. M. Ball1J. Whitehead2C. Leblanc3A. J. L. Shillings4A. S. Mahajan5H. Oetjen6J. D. Lee7C. E. Jones8J. R. Dorsey9M. Gallagher10R. L. Jones11J. M. C. Plane12P. Potin13G. McFiggans14Department of Physics and Astronomy, University of Leicester, Leicester, UKDepartment of Chemistry, University of Leicester, Leicester, UKSchool of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UKStation Biologique de Roscoff, UPMC-CNRS, UMR 7139, Roscoff, FranceDepartment of Chemistry, University of Cambridge, Cambridge, UKSchool of Chemistry, University of Leeds, Leeds, UKSchool of Chemistry, University of Leeds, Leeds, UKDepartment of Chemistry, University of York, York, UKDepartment of Chemistry, University of York, York, UKSchool of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UKSchool of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UKDepartment of Chemistry, University of Cambridge, Cambridge, UKSchool of Chemistry, University of Leeds, Leeds, UKStation Biologique de Roscoff, UPMC-CNRS, UMR 7139, Roscoff, FranceSchool of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UKIodine emissions from the dominant six macroalgal species in the coastal regions around Roscoff, France, have been modelled to support the Reactive Halogens in the Marine Boundary Layer Experiment (RHaMBLe) undertaken in September 2006. A two-dimensional model is used to explore the relationship between geographically resolved regional emissions (based on maps of seaweed beds in the area and seaweed I<sub>2</sub> emission rates previously measured in the laboratory) and in situ point and line measurements of I<sub>2</sub> performed respectively by a broadband cavity ringdown spectroscopy (BBCRDS) instrument sited on the shoreline and a long-path differential optical absorption spectroscopy (LP-DOAS) instrument sampling over an extended light path to an off-shore island. The modelled point and line I<sub>2</sub> concentrations compare quantitatively with BBCRDS and LP-DOAS measurements, and provide a link between emission fields and the different measurement geometries used to quantify atmospheric I<sub>2</sub> concentrations during RHaMBLe. Total I<sub>2</sub> emissions over the 100 km<sup>2</sup> region around Roscoff are calculated to be 1.7×10<sup>19</sup> molecules per second during the lowest tides. <br><br> During the night, the model replicates I<sub>2</sub> concentrations up to 50 pptv measured along the LP-DOAS instrument's line of sight, and predicts spikes of several hundred pptv in certain conditions. Point I<sub>2</sub> concentrations up to 50 pptv are also calculated at the measurement site, in broad agreement with the BBCRDS observations. Daytime measured concentrations of I<sub>2</sub> at the site correlate with modelled production and transport processes. However substantial recycling of the photodissociated I<sub>2</sub> is required for the model to quantitatively match measured concentrations. This result corroborates previous modelling of iodine and NO<sub>x</sub> chemistry in the semi-polluted marine boundary layer which proposed a mechanism for recycling I<sub>2</sub> via the formation, transport and subsequent reactions of the IONO<sub>2</sub> reservoir compound. <br><br> The methodology presented in this paper provides a tool for linking spatially distinct measurements to inhomogeneous and temporally varying emission fields.http://www.atmos-chem-phys.net/10/11823/2010/acp-10-11823-2010.pdf |
| spellingShingle | R. J. Leigh S. M. Ball J. Whitehead C. Leblanc A. J. L. Shillings A. S. Mahajan H. Oetjen J. D. Lee C. E. Jones J. R. Dorsey M. Gallagher R. L. Jones J. M. C. Plane P. Potin G. McFiggans Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff Atmospheric Chemistry and Physics |
| title | Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff |
| title_full | Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff |
| title_fullStr | Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff |
| title_full_unstemmed | Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff |
| title_short | Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff |
| title_sort | measurements and modelling of molecular iodine emissions transport and photodestruction in the coastal region around roscoff |
| url | http://www.atmos-chem-phys.net/10/11823/2010/acp-10-11823-2010.pdf |
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