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@ARTICLE{Fischer:858089,
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 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 / Discussions Discussions
[...]},
volume = {1179},
issn = {1680-7375},
address = {Katlenburg-Lindau},
publisher = {EGU},
reportid = {FZJ-2018-07007},
pages = {1 - 29},
year = {2018},
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 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 approx. 1 and 6cm/s, 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},
doi = {10.5194/acp-2018-1179},
url = {https://juser.fz-juelich.de/record/858089},
}