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@INPROCEEDINGS{Rosanka:902273,
author = {Rosanka, Simon},
title = {{I}nfluence of in-cloud oxidation of organic compounds on
tropospheric ozone},
reportid = {FZJ-2021-04136},
year = {2021},
abstract = {<p>Large parts of the troposphere are affected by clouds,
whose aqueous-phase chemistry differs significantly from
gas-phase chemistry. Box-model studies have demonstrated
that clouds influence the tropospheric oxidation capacity.
However, most global atmospheric models do not represent
this chemistry reasonably well and are largely limited to
sulfur oxidation. Therefore, we have developed the
$J\ülich$ Aqueous-phase Mechanism of Organic Chemistry
(JAMOC), making a detailed in-cloud oxidation model of
oxygenated volatile organic compounds (OVOCs) readily
available for box as well as for regional and global
simulations that are affordable with modern supercomputers.
JAMOC includes the phase transfer of species containing up
to ten carbon atoms, and the aqueous-phase reactions of a
selection of species containing up to four carbon atoms,
e.g., ethanol, acetaldehyde, glyoxal. The impact of in-cloud
chemistry on tropospheric composition is assessed on a
regional and global scale by performing a combination of
box-model studies using the Chemistry As A Boxmodel
Application (CAABA) and the global atmospheric model
ECHAM/MESSy (EMAC). These models are capable to represent
the described processes explicitly and integrate the
corresponding ODE system with a Rosenbrock
$solver.\ </p><p>Overall,$ the explicit in-cloud
oxidation leads to a reduction of predicted OVOCs levels. By
comparing EMAC's prediction of methanol abundance to
spaceborne retrievals from the Infrared Atmospheric Sounding
Interferometer (IASI), a reduction in EMAC's overestimation
is observed in the tropics. Further, the in-cloud OVOC
oxidation shifts the hydroperoxyl radicals (HO<sub>2</sub>)
production from the gas- to the aqueous-phase. As a result,
the in-cloud destruction (scavenging) of ozone
(O<sub>3</sub>) by the superoxide anion
(O<sub>2</sub><sup>-</sup>) is enhanced and accompanied by a
reduction in both sources and sinks of tropospheric
O<sub>3</sub> in the gas phase. By considering only the
in-cloud sulfur oxidation by O<sub>3</sub>, about 13 Tg
a<sup>-1</sup> of O<sub>3</sub> are scavenged, which
increases to 336 Tg a<sup>-1</sup> when JAMOC is used. With
the full oxidation scheme, the highest O<sub>3</sub>
reduction of 12 $\%$ is predicted in the upper
troposphere/lower stratosphere (UTLS). Based on the IASI
O<sub>3</sub> retrievals, it is demonstrated that these
changes in the free troposphere significantly reduce the
modelled tropospheric O<sub>3</sub> columns, which are known
to be generally overestimated by global atmospheric models.
Finally, the relevance of aqueous-phase oxidation of
organics for ozone in hazy polluted regions will be
presented. $\ </p>$},
month = {Apr},
date = {2021-04-19},
organization = {EGU General Assembly 2021, Online ( ),
19 Apr 2021 - 30 Apr 2021},
subtyp = {Other},
cin = {IEK-8},
cid = {I:(DE-Juel1)IEK-8-20101013},
pnm = {2111 - Air Quality (POF4-211)},
pid = {G:(DE-HGF)POF4-2111},
typ = {PUB:(DE-HGF)6},
doi = {10.5194/egusphere-egu21-10276},
url = {https://juser.fz-juelich.de/record/902273},
}