Atmospheric Chemistry and Physics (Jan 2011)

Bromoform in the tropical boundary layer of the Maritime Continent during OP3

  • J. A. Pyle,
  • M. J. Ashfold,
  • N. R. P. Harris,
  • A. D. Robinson,
  • N. J. Warwick,
  • G. D. Carver,
  • B. Gostlow,
  • L. M. O'Brien,
  • A. J. Manning,
  • S. M. Phang,
  • S. E. Yong,
  • K. P. Leong,
  • E. H. Ung,
  • S. Ong

DOI
https://doi.org/10.5194/acp-11-529-2011
Journal volume & issue
Vol. 11, no. 2
pp. 529 – 542

Abstract

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We report measurements of bromoform made by gas chromatography during the OP3 campaign in 2008. Measurements were made simultaneously for a few days at the World Meteorological Organization (WMO) Global Atmospheric Watch (GAW) site in the Danum Valley, a rainforest location in Sabah, Borneo, and at a nearby coastal site at Kunak. Background values at Kunak were higher than those measured in the rainforest (2–5 ppt compared with 1 ppt) and excursions away from the background were very much higher, reaching 10 s of ppt. Measurements of C<sub>2</sub>Cl<sub>4</sub>, an industrial tracer, showed no significant difference in background at the two sites. Modelling using two different models can reproduce a number of the observed features. The data are consistent with a strong, local coastal source of bromoform in eastern Sabah and can be used to infer the strength of the source of bromoform in South East Asia. However, they provide only a very weak constraint on global emissions. The global model results highlight the difficulty for short-lived species of extrapolating limited duration, local measurements to a global source.