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| Titel |
Long-term observations of glyoxal and formaldehyde over the Eastern Pacific Ocean |
| VerfasserIn |
A. S. Mahajan, C. Prados-Roman, T. D. Hay, J. C. Gómez Martín, C. Ordóñez, S. MacDonald, J. M. C. Plane, A. Saiz-Lopez |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250066389
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| Zusammenfassung |
| Glyoxal ((CHO)2) and formaldehyde (HCHO) are important intermediates in the breakdown
of many volatile organic compounds (VOCs). Glyoxal is also a possible source of secondary
organic aerosol (SOA) through its condensation and coagulation. A recent study has shown
the presence of high levels of glyoxal in the Pacific marine boundary layer (MBL), which
cannot be explained by precursors such as isoprene and suggests other unknown oceanic
sources of glyoxal (1).
Observations of glyoxal and formaldehyde were made during two field campaigns in the
Eastern Pacific MBL, aiming at a better understanding of the chemistry of VOCs and their
temporal and geographical distribution in this region. The first campaign, HaloCarbon Air
Sea Transect-Pacific (HaloCAST-P), was a one-month ship-based study on a scientific cruise
from Chile to Seattle during March-April 2010. The second study, Climate and HAlogen
Reactivity tropicaL EXperiment (CHARLEX), is an on going 16-month ground-based study
on the Galapagos Islands, Ecuador, from September 2010 to present. Observations of (CHO)2
and HCHO were made using long path differential optical absorption spectrometry
(LP-DOAS) and multi axis DOAS (MAX-DOAS). In addition, observations of
reactive halogens, ozone, NOx, meteorological data, radiosondes, ozone sondes and
ultrafine and total aerosol number concentration were also obtained enabling deeper
understanding of the possible sources and the impacts of (CHO)2 and HCHO in this
environment.
We present the temporal evolution of (CHO)2 and HCHO over the entire measurement
period. LP-DOAS and MAX-DOAS data are used in conjunction with a radiative transfer
model to construct the vertical profile in the MBL. The correlation to biotic and abiotic
variables is explored in detail. Additionally, using a one-dimensional model, we try to
elucidate the various parameters affecting the strong seasonal variation and calculate the
fluxes necessary to explain the observations.
(1) Sinreich R. et al. Atmos. Chem. Phys. (2010) 10, 11359-11371. |
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