Atmospheric bromoform at Cape Point, South Africa: an initial fixed-point data set on the African continent
Bromoform mixing ratios in marine air were measured at Cape Point Global Atmospheric Watch Station, South Africa. This represents the first such bromoform data set recorded at this location. Manual daily measurements were made during a month-long field campaign (austral spring 2011) using a gas...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/5785/2018/acp-18-5785-2018.pdf |
| Summary: | Bromoform mixing ratios in marine air were measured at Cape Point Global
Atmospheric Watch Station, South Africa. This represents the first such
bromoform data set recorded at this location. Manual daily measurements were
made during a month-long field campaign (austral spring 2011) using a gas
chromatograph-electron capture detector (GC-ECD) with a custom-built front
end thermal desorption trap. The measured concentrations ranged between 4.4
and 64.6 (± 22.2 %) ppt with a mean of
24.8 ± 14.8 ppt. The highest mixing ratios recorded here
occurred at, or shortly after, low tide. The diurnal cycle exhibited a
morning and evening maximum with lower concentrations throughout the rest of
the day. Initial analysis of the data presented indicates that the local kelp
beds were the dominant source of the bromoform reported. A concentration-weighted trajectory analysis of the bromoform measurements suggests that two
offshore source areas may exist. These source areas appear to be centred on
the Agulhas retroflection and extend from St Helena Bay to the southwest. |
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| ISSN: | 1680-7316 1680-7324 |