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Organic trace gases of oceanic origin observed at South Pole during ISCAT 2000
- Source :
-
Atmospheric Environment . Oct2004, Vol. 38 Issue 32, p5463-5472. 10p. - Publication Year :
- 2004
-
Abstract
- Volatile organic compounds (VOCs) were measured at the South Pole (SP) from late Austral spring to mid-summer 2000 as part of the Investigation of Sulfur Chemistry in the Antarctic Troposphere Program (ISCAT-2000). This paper focuses on VOCs that are directly emitted from the ocean, specifically dimethyl sulfide (DMS), methyl nitrate (CH3ONO2), methyl iodide (CH3I) and bromoform (CHBr3). A partial seasonal cycle of these gases was also recorded during the year following ISCAT-2000. During the summer, the SP periodically receives relatively fresh marine air containing short-lived oceanic trace gases, such as DMS (<f>τ≈1</f> day). However, DMS was not detected at the SP until January even though DMS emissions from the Southern Ocean typically start peaking in November and elevated levels of other ocean-derived VOCs, including CH3ONO2 and CHBr3, were observed in mid-November. We speculate that in November and December most of the DMS is oxidized before it reaches the SP: a strong correlation between CH3ONO2 and methane sulfonate (MSA), an oxidation product of DMS, supports this hypothesis. Based on a limited number of samples taken over the course of one year, CH3ONO2 apparently accumulates to a quasi-steady-state level over the SP in winter, most likely due to continuing emissions of the compound coupled with a lower rate of photochemical destruction. Oceanic emissions were concluded to be the dominant source of alkyl nitrates at the SP; this is in sharp contrast to northern high latitudes where total alkyl nitrate mixing ratios are dominated by urban sources. [Copyright &y& Elsevier]
- Subjects :
- *ORGANIC compounds
*BROMOFORM
*OCEAN
*NITRATES
Subjects
Details
- Language :
- English
- ISSN :
- 13522310
- Volume :
- 38
- Issue :
- 32
- Database :
- Academic Search Index
- Journal :
- Atmospheric Environment
- Publication Type :
- Academic Journal
- Accession number :
- 14416110
- Full Text :
- https://doi.org/10.1016/j.atmosenv.2004.03.072