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Titel |
A laboratory characterisation of inorganic iodine emissions from the sea surface: dependence on oceanic variables and parameterisation for global modelling |
VerfasserIn |
S. M. MacDonald, J. C. Gómez Martín, R. Chance, S. Warriner, A. Saiz-Lopez, L. J. Carpenter, J. M. C. Plane |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 11 ; Nr. 14, no. 11 (2014-06-12), S.5841-5852 |
Datensatznummer |
250118790
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Publikation (Nr.) |
copernicus.org/acp-14-5841-2014.pdf |
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Zusammenfassung |
Reactive iodine compounds play a significant role in the atmospheric
chemistry of the oceanic boundary layer by influencing the oxidising
capacity through catalytically removing O3 and altering the HOx
and NOx balance. The sea-to-air flux of iodine over the open ocean is
therefore an important quantity in assessing these impacts on a global
scale. This paper examines the effect of a number of relevant environmental
parameters, including water temperature, salinity and organic compounds, on
the magnitude of the HOI and I2 fluxes produced from the uptake of
O3 and its reaction with iodide ions in aqueous solution. The results
of these laboratory experiments and those reported previously (Carpenter et
al., 2013), along with sea surface iodide concentrations
measured or inferred from measurements of dissolved total iodine and iodate
reported in the literature, were then used to produce parameterised
expressions for the HOI and I2 fluxes as a function of wind speed,
sea-surface temperature and O3. These expressions were used in the
Tropospheric HAlogen chemistry MOdel (THAMO) to compare with MAX-DOAS
measurements of iodine monoxide (IO) performed during the HaloCAST-P cruise
in the eastern Pacific ocean (Mahajan et al., 2012). The
modelled IO agrees reasonably with the field observations, although
significant discrepancies are found during a period of low wind speeds
(< 3 m s−1), when the model overpredicts IO by up to a factor
of 3. The inorganic iodine flux contributions to IO are found to be
comparable to, or even greater than, the contribution of organo-iodine
compounds and therefore its inclusion in atmospheric models is important to
improve predictions of the influence of halogen chemistry in the marine
boundary layer. |
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