Characterization of ozone deposition to a mixed oak–hornbeam forest – flux measurements at five levels above and inside the canopy and their interactions with nitric oxide
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Published:2018-12-18
Issue:24
Volume:18
Page:17945-17961
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ISSN:1680-7324
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Container-title:Atmospheric Chemistry and Physics
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language:en
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Short-container-title:Atmos. Chem. Phys.
Author:
Finco Angelo, Coyle MhairiORCID, Nemitz EikoORCID, Marzuoli RiccardoORCID, Chiesa Maria, Loubet Benjamin, Fares SilvanoORCID, Diaz-Pines EugenioORCID, Gasche RainerORCID, Gerosa GiacomoORCID
Abstract
Abstract. A 1-month field campaign of ozone (O3) flux measurements along a
five-level vertical profile above, inside and below the canopy was run in a
mature broadleaf forest of the Po Valley, northern Italy. The study aimed to
characterize O3 flux dynamics and their interactions with
nitrogen oxides (NOx) fluxes from the forest soil and the
atmosphere above the canopy. Ozone fluxes measured at the levels above the
canopy were in good agreement, thus confirming the validity of the constant
flux hypothesis, while below-canopy O3 fluxes were lower than
above. However, at the upper canopy edge O3 fluxes were
surprisingly higher than above during the morning hours. This was attributed
to a chemical O3 sink due to a reaction with the nitric oxide (NO)
emitted from soil and deposited from the atmosphere, thus converging at the
top of the canopy. Moreover, this mechanism was favored by the morning
coupling between the forest and the atmosphere, while in the afternoon the
fluxes at the upper canopy edge became similar to those of the levels above
as a consequence of the in-canopy stratification. Nearly 80 % of the
O3 deposited to the forest ecosystem was removed by the canopy by
stomatal deposition, dry deposition on physical surfaces and by ambient
chemistry reactions (33.3 % by the upper canopy layer and 46.3 % by the
lower canopy layer). Only a minor part of O3 was removed by the
understorey vegetation and the soil surface (2 %), while the remaining
18.2 % was consumed by chemical reaction with NO emitted from soil. The
collected data could be used to improve the O3 risk assessment for
forests and to test the predicting capability of O3 deposition
models. Moreover, these data could help multilayer canopy models to separate
the influence of ambient chemistry vs. O3 dry deposition on the
observed fluxes.
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference79 articles.
1. Acton, W. J. F., Schallhart, S., Langford, B., Valach, A., Rantala, P., Fares,
S., Carriero, G., Tillmann, R., Tomlinson, S. J., Dragosits, U., Gianelle, D.,
Hewitt, C. N., and Nemitz, E.: Canopyscale flux measurements and bottom-up
emission estimates of volatile organic compounds from a mixed oak and hornbeam
forest in northern Italy, Atmos. Chem. Phys., 16, 7149–7170, https://doi.org/10.5194/acp-16-7149-2016, 2016. 2. Altimir, N., Tuovinen, J.-P., Vesala, T., Kulmala, M., and Hari, P.: Measurements
of ozone removal to Scots pine shoots: calibration of a stomatal uptake model
including the non-stomatal component, Atmos. Environ., 38, 2387–2398, 2004. 3. Altimir, N., Kolari, P., Tuovinen, J.-P., Vesala, T., Bäck, J., Suni, T.,
Kulmala, M., and Hari, P.: Foliage surface ozone deposition: a role for surface
moisture?, Biogeosciences, 3, 209–228, https://doi.org/10.5194/bg-3-209-2006, 2006. 4. Amthor, J. S., Goulden, M. L., Munger, J. W., and Wofsy, S. C.: Testing a
mechanistic model of forest-canopy mass and energy exchange using eddy
correlation: carbon dioxide and ozone uptake by a mixed oak-maple stand, Funct.
Plant Biol., 21, 623–651, 1994. 5. Arya, S. P.: Introduction to Micrometeorology, Academic Press, San Diego, USA, 415 pp., 2001.
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