Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layer
Time series observations of molecular iodine (I<sub>2</sub>), iodine oxides (IO, OIO), bromine oxide (BrO), and the nitrate radical (NO<sub>3</sub>) in the mid-latitude coastal marine boundary layer (MBL) are reported. Measurements were made using a new long-path DOAS instrum...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2006-01-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/6/1513/2006/acp-6-1513-2006.pdf |
| _version_ | 1818945148836380672 |
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| author | A. Saiz-Lopez J. A. Shillito H. Coe J. M. C. Plane |
| author_facet | A. Saiz-Lopez J. A. Shillito H. Coe J. M. C. Plane |
| author_sort | A. Saiz-Lopez |
| collection | DOAJ |
| description | Time series observations of molecular iodine (I<sub>2</sub>), iodine oxides (IO, OIO), bromine oxide (BrO), and the nitrate radical (NO<sub>3</sub>) in the mid-latitude coastal marine boundary layer (MBL) are reported. Measurements were made using a new long-path DOAS instrument during a summertime campaign at Mace Head on the <i>B</i><sup>3</sup>Π(0<sup>+</sup><sub>u</sub>)-<i>X</i><sup>1</sup>Σ<sup>+</sup><sub>g</sub> electronic transition between 535 and 575 nm. The I<sub>2</sub> mixing ratio was found to vary from below the detection limit (~5 ppt) up to a nighttime maximum of 93 ppt. Along with I<sub>2</sub>, observations of IO, OIO and NO<sub>3</sub> were also made during the night. Surprisingly, IO and OIO were detected at mixing ratios up to 2.5 and 10.8 ppt, respectively. A model is employed to show that the reaction between I<sub>2</sub> and NO<sub>3</sub> is the likely nighttime source of these radicals. The BrO mixing ratio varied from below the detection limit at night (~1 ppt) to a maximum of 6 ppt in the first hours after sunrise. A bromine chemistry model is used to simulate the diurnal behaviour of the BrO radical, demonstrating the importance of halogen recycling through sea-salt aerosol. In the same campaign a zenith sky DOAS was employed to determine the column density variation of NO<sub>3</sub> as a function of solar zenith angle (SZA) during sunrise, from which vertical profiles of NO<sub>3</sub> through the troposphere were obtained. On several occasions a positive gradient of NO<sub>3</sub> was observed over the first 2 km, possibly due to dimethyl sulphide (DMS) removing NO<sub>3</sub> at the ocean surface. |
| first_indexed | 2024-12-20T07:54:31Z |
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| id | doaj.art-2e6d281721b04cd2a9a9b30d4c442d90 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-20T07:54:31Z |
| publishDate | 2006-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-2e6d281721b04cd2a9a9b30d4c442d902022-12-21T19:47:45ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242006-01-016615131528Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layerA. Saiz-LopezJ. A. ShillitoH. CoeJ. M. C. PlaneTime series observations of molecular iodine (I<sub>2</sub>), iodine oxides (IO, OIO), bromine oxide (BrO), and the nitrate radical (NO<sub>3</sub>) in the mid-latitude coastal marine boundary layer (MBL) are reported. Measurements were made using a new long-path DOAS instrument during a summertime campaign at Mace Head on the <i>B</i><sup>3</sup>Π(0<sup>+</sup><sub>u</sub>)-<i>X</i><sup>1</sup>Σ<sup>+</sup><sub>g</sub> electronic transition between 535 and 575 nm. The I<sub>2</sub> mixing ratio was found to vary from below the detection limit (~5 ppt) up to a nighttime maximum of 93 ppt. Along with I<sub>2</sub>, observations of IO, OIO and NO<sub>3</sub> were also made during the night. Surprisingly, IO and OIO were detected at mixing ratios up to 2.5 and 10.8 ppt, respectively. A model is employed to show that the reaction between I<sub>2</sub> and NO<sub>3</sub> is the likely nighttime source of these radicals. The BrO mixing ratio varied from below the detection limit at night (~1 ppt) to a maximum of 6 ppt in the first hours after sunrise. A bromine chemistry model is used to simulate the diurnal behaviour of the BrO radical, demonstrating the importance of halogen recycling through sea-salt aerosol. In the same campaign a zenith sky DOAS was employed to determine the column density variation of NO<sub>3</sub> as a function of solar zenith angle (SZA) during sunrise, from which vertical profiles of NO<sub>3</sub> through the troposphere were obtained. On several occasions a positive gradient of NO<sub>3</sub> was observed over the first 2 km, possibly due to dimethyl sulphide (DMS) removing NO<sub>3</sub> at the ocean surface.http://www.atmos-chem-phys.net/6/1513/2006/acp-6-1513-2006.pdf |
| spellingShingle | A. Saiz-Lopez J. A. Shillito H. Coe J. M. C. Plane Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layer Atmospheric Chemistry and Physics |
| title | Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layer |
| title_full | Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layer |
| title_fullStr | Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layer |
| title_full_unstemmed | Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layer |
| title_short | Measurements and modelling of I<sub>2</sub>, IO, OIO, BrO and NO<sub>3</sub> in the mid-latitude marine boundary layer |
| title_sort | measurements and modelling of i sub 2 sub io oio bro and no sub 3 sub in the mid latitude marine boundary layer |
| url | http://www.atmos-chem-phys.net/6/1513/2006/acp-6-1513-2006.pdf |
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