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 (CH 3I) 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 (τ≈1 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 CHBr 3, 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.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 5463-5472 |
| Number of pages | 10 |
| Journal | Atmospheric Environment |
| Volume | 38 |
| Issue number | 32 |
| DOIs | |
| State | Published - Oct 2004 |
| Externally published | Yes |
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Keywords
- Alkyl nitrates
- Bromoform
- DMS
- Methyl iodide
- Oceanic emissions
- Photochemistry
- South pole
ASJC Scopus subject areas
- Atmospheric Science
- Environmental Science(all)
- Pollution
Cite this
Organic trace gases of oceanic origin observed at South Pole during ISCAT 2000. / Swanson, Aaron L.; Davis, Douglas D.; Arimoto, Richard; Roberts, Pauline; Atlas, Elliot L; Flocke, Frank; Meinardi, Simone; Sherwood Rowland, F.; Blake, Donald R.
In: Atmospheric Environment, Vol. 38, No. 32, 10.2004, p. 5463-5472.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Organic trace gases of oceanic origin observed at South Pole during ISCAT 2000
AU - Swanson, Aaron L.
AU - Davis, Douglas D.
AU - Arimoto, Richard
AU - Roberts, Pauline
AU - Atlas, Elliot L
AU - Flocke, Frank
AU - Meinardi, Simone
AU - Sherwood Rowland, F.
AU - Blake, Donald R.
PY - 2004/10
Y1 - 2004/10
N2 - 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 (CH 3I) 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 (τ≈1 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 CHBr 3, 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.
AB - 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 (CH 3I) 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 (τ≈1 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 CHBr 3, 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.
KW - Alkyl nitrates
KW - Bromoform
KW - DMS
KW - Methyl iodide
KW - Oceanic emissions
KW - Photochemistry
KW - South pole
UR - http://www.scopus.com/inward/record.url?scp=4444348522&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4444348522&partnerID=8YFLogxK
U2 - 10.1016/j.atmosenv.2004.03.072
DO - 10.1016/j.atmosenv.2004.03.072
M3 - Article
VL - 38
SP - 5463
EP - 5472
JO - Atmospheric Environment
JF - Atmospheric Environment
SN - 1352-2310
IS - 32
ER -