|
Titel |
Atmospheric sulfur cycling in the southeastern Pacific – longitudinal distribution, vertical profile, and diel variability observed during VOCALS-REx |
VerfasserIn |
M. Yang, B. J. Huebert, B. W. Blomquist, S. G. Howell, L. M. Shank, C. S. McNaughton, A. D. Clarke, L. N. Hawkins, L. M. Russell, D. S. Covert, D. J. Coffman, T. S. Bates, P. K. Quinn, N. Zagorac, A. R. Bandy, S. P. Szoeke, P. D. Zuidema, S. C. Tucker, W. A. Brewer, K. B. Benedict, J. L. Collett |
Medientyp |
Artikel
|
Sprache |
Englisch
|
ISSN |
1680-7316
|
Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 10 ; Nr. 11, no. 10 (2011-05-31), S.5079-5097 |
Datensatznummer |
250009772
|
Publikation (Nr.) |
copernicus.org/acp-11-5079-2011.pdf |
|
|
|
Zusammenfassung |
Dimethylsulfide (DMS) emitted from the ocean is a biogenic precursor gas for
sulfur dioxide (SO2) and non-sea-salt sulfate aerosols
(SO42−). During the VAMOS-Ocean-Cloud-Atmosphere-Land Study
Regional Experiment (VOCALS-REx) in 2008, multiple instrumented platforms
were deployed in the Southeastern Pacific (SEP) off the coast of Chile and
Peru to study the linkage between aerosols and stratocumulus clouds. We
present here observations from the NOAA Ship Ronald H. Brown and the NSF/NCAR C-130
aircraft along ~20° S from the coast (70° W) to a remote marine
atmosphere (85° W). While SO42− and SO2 concentrations
were distinctly elevated above background levels in the coastal marine
boundary layer (MBL) due to anthropogenic influence (~800 and 80 pptv,
respectively), their concentrations rapidly decreased west of 78° W
(~100 and 25 pptv). In the remote region, entrainment from the free
troposphere (FT) increased MBL SO2 burden at a rate of 0.05 ± 0.02 μmoles m−2 day−1 and diluted MBL SO42 burden at a
rate of 0.5 ± 0.3 μmoles m−2 day−1, while the sea-to-air
DMS flux (3.8 ± 0.4 μmoles m−2 day−1) remained the
predominant source of sulfur mass to the MBL. In-cloud oxidation was found
to be the most important mechanism for SO2 removal and in situ
SO42− production. Surface SO42− concentration in the
remote MBL displayed pronounced diel variability, increasing rapidly in the
first few hours after sunset and decaying for the rest of the day. We
theorize that the increase in SO42− was due to nighttime
recoupling of the MBL that mixed down cloud-processed air, while decoupling
and sporadic precipitation scavenging were responsible for the daytime
decline in SO42−. |
|
|
Teil von |
|
|
|
|
|
|