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@ARTICLE{Fischer:868095,
author = {Fischer, Horst and Axinte, Raoul and Bozem, Heiko and
Crowley, John N. and Ernest, Cheryl and Gilge, Stefan and
Hafermann, Sascha and Harder, Hartwig and Hens, Korbinian
and Janssen, Ruud H. H. and Königstedt, Rainer and
Kubistin, Dagmar and Mallik, Chinmay and Martinez, Monica
and Novelli, Anna and Parchatka, Uwe and Plass-Dülmer,
Christian and Pozzer, Andrea and Regelin, Eric and Reiffs,
Andreas and Schmidt, Torsten and Schuladen, Jan and
Lelieveld, Jos},
title = {{D}iurnal variability, photochemical production and loss
processes of hydrogen peroxide in the boundary layer over
{E}urope},
journal = {Atmospheric chemistry and physics},
volume = {19},
number = {18},
issn = {1680-7324},
address = {Katlenburg-Lindau},
publisher = {EGU},
reportid = {FZJ-2019-06686},
pages = {11953 - 11968},
year = {2019},
abstract = {Hydrogen peroxide (H2O2) plays a significant role in the
oxidizing capacity of the atmosphere. It is an efficient
oxidant in the liquid phase and serves as a temporary
reservoir for the hydroxyl radical (OH), the most important
oxidizing agent in the gas phase. Due to its high
solubility, removal of H2O2 due to wet and dry deposition is
efficient, being a sink of HOx (OH+HO2) radicals. In the
continental boundary layer, the H2O2 budget is controlled by
photochemistry, transport and deposition processes. Here we
use in situ observations of H2O2 and account for chemical
source and removal mechanisms to study the interplay between
these processes. The data were obtained during five
ground-based field campaigns across Europe from 2008 to 2014
and bring together observations in a boreal forest, two
mountainous sites in Germany, and coastal sites in Spain and
Cyprus. Most campaigns took place in the summer, while the
measurements in the south-west of Spain took place in early
winter. Diel variations in H2O2 are strongly site-dependent
and indicate a significant altitude dependence. While
boundary-layer mixing ratios of H2O2 at low-level sites show
classical diel cycles with the lowest values in the early
morning and maxima around local noon, diel profiles are
reversed on mountainous sites due to transport from the
nocturnal residual layer and the free troposphere. The
concentration of hydrogen peroxide is largely governed by
its main precursor, the hydroperoxy radical (HO2), and shows
significant anti-correlation with nitrogen oxides (NOx) that
remove HO2. A budget calculation indicates that in all
campaigns, the noontime photochemical production rate
through the self-reaction of HO2 radicals was much larger
than photochemical loss due to reaction with OH and
photolysis, and that dry deposition is the dominant loss
mechanism. Estimated dry deposition velocities varied
between approximately 1 and 6 cm s−1, with relatively
high values observed during the day in forested regions,
indicating enhanced uptake of H2O2 by vegetation. In order
to reproduce the change in H2O2 mixing ratios between
sunrise and midday, a variable contribution from transport
$(10 \%–100 \%)$ is required to balance net
photochemical production and deposition loss. Transport is
most likely related to entrainment from the residual layer
above the nocturnal boundary layer during the growth of the
boundary layer in the morning.},
cin = {IEK-8},
ddc = {550},
cid = {I:(DE-Juel1)IEK-8-20101013},
pnm = {243 - Tropospheric trace substances and their
transformation processes (POF3-243)},
pid = {G:(DE-HGF)POF3-243},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000488022200003},
doi = {10.5194/acp-19-11953-2019},
url = {https://juser.fz-juelich.de/record/868095},
}