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@ARTICLE{Derstroff:819751,
author = {Derstroff, Bettina and Hüser, Imke and Sander, Rolf and
Bourtsoukidis, Efstratios and Crowley, John N. and Fischer,
Horst and Gromov, Sergey and Harder, Hartwig and
Kesselmeier, Jürgen and Lelieveld, Jos and Mallik, Chinmay
and Martinez, Monica and Novelli, Anna and Parchatka, Uwe
and Phillips, Gavin J. and Sauvage, Carina and Schuladen,
Jan and Stönner, Christof and Tomsche, Laura and Williams,
Jonathan},
title = {{V}olatile organic compounds ({VOC}s) in photochemically
aged air from the {E}astern and {W}estern {M}editerranean},
journal = {Atmospheric chemistry and physics / Discussions},
volume = {0},
issn = {1680-7375},
address = {Katlenburg-Lindau},
publisher = {EGU},
reportid = {FZJ-2016-05347},
pages = {},
year = {2016},
abstract = {During the summertime CYPHEX campaign (CYprus PHotochemical
EXperiment 2014) in the Eastern Mediterranean, multiple
volatile organic compounds (VOCs) were measured from a
650 m hilltop site in western Cyprus
(34°57' N/32°23' E). Periodic shifts in the northerly
Etesian winds resulted in the site being alternately
impacted by photochemically processed emissions from Western
(Spain, France, Italy) and Eastern (Turkey, Greece) Europe.
In this study we examine the temporal variation of VOCs at
the site. The sparse Mediterranean scrub vegetation
generated diel cycles in the reactive biogenic hydrocarbon
isoprene, from below detection limit at night to 100 pptv
by day on average. In contrast, the oxygenated volatile
organic compounds (OVOCs) methanol and acetone exhibited no
diel cycle and were approximately an order of magnitude
higher in mixing ratio (range: 1–8 ppbv) than the
locally emitted isoprene (up to 320 pptv), total
monoterpenes (up to 250 pptv) and aromatic compounds such
as benzene and toluene (up to 100 pptv, spikes up to
400 pptv). Acetic acid was present at mixing ratios
between 0.05 and 4 ppbv and followed a pronounced diel
cycle in one specific period, which was related to local
production and loss and local meteorological effects. During
the rest of the campaign the impact of the free troposphere
and long distance transport from source regions dominated
over local processes and diel cycles were not observed. The
Lagrangian model FLEXPART was used to determine transport
patterns and photochemical processing times of air masses
originating from Eastern and Western Europe. Eastern and
Western European air masses showed distinct trace gas
concentrations, with ca. $20 \%$ higher ozone and ca.
$30–50 \%$ higher values for most of the OVOCs observed
from the East. Using the FLEXPART calculated transport time,
the contribution of photochemical processing, sea surface
contact and dilution was estimated. Methanol, acetone and
acetic acid all decreased with residence time in the marine
boundary layer (MBL) with loss rates of
0.1 ± 0.01 ppbv/h, 0.06 ± 0.01 ppbv/h, 0.05 ±
0.01 ppbv/h from Eastern Europe and
0.06 ± 0.01 ppbv/h, 0.02 ± 0.004 ppbv/h and
0.03 ± 0.004 ppbv/h from Western Europe,
respectively. The most soluble species, acetic acid, showed
the lowest loss rates, indicating that solubility limited
deposition to the ocean was not the only factor and that
turbulent transport, plume dilution, microbial consumption
within the surface of the ocean and especially entrainment
from the free troposphere may also be important.
Correlations between acetone, methanol and acetic acid were
rather weak in western air masses (r2 = 0.52–0.62),
but were stronger in air masses measured after the shorter
transport time from the East (r2 = 0.53–0.81).},
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-2016-746},
url = {https://juser.fz-juelich.de/record/819751},
}