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| Titel |
Variation of eddy covariance ozone flux and its main controlling factors over corn field in North-China Plain |
| VerfasserIn |
Zhilin Zhu, Xiaomin Sun, Yunshe Dong, Fenghua Zhao, Franz X. Meixner |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250073517
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| Zusammenfassung |
| High concentration ozone in the troposphere has negative effect on ecosystem and the indexes
based on ozone flux (Fo) are considered the better metric than that based on O3
concentration. To investigate the effect of ozone on cropland ecosystem, ozone concentration,
deposition velocity and ozone flux was measured by eddy covariance technique at corn field
in North-China-Plain. The results show that (1) there was a diurnal change pattern in O3
concentration, with low (16.5 nL L-1) and high (60.1 nL L-1) mean O3 concentrations at
about 6:30 and 16:00, respectively. Mean O3 concentration in daytime (6:00-18:00)
and nighttime (18:00-6:00) were 39.8 ± 23.1 nL L-1 and 20.7 ± 14.1 nL L-1
(mean ± SE), respectively. O3 concentration is mainly affected by solar radiation
and temperature. (2) The diurnal course of mean deposition velocity (V d) can be
divided into 4 phases: weak and stable process in nighttime; fast increasing in the
early morning; strong and steady changes around noon and quickly decreasing
in the later afternoon. Mean V d were 0.29cm s-1and 0.09cm s-1in daytime and
nighttime, respectively. The magnitude of V d is influenced by corn growth period, and
its diurnal change is significantly related to radiation and relative humidity. (3)
Mean Fo were -317.7 ng m-2 s-1 and -70.2 ng m-2 s-1 in daytime and nighttime,
respectively. There are evident relationships between Fo and CO2/H2O fluxes.
By comparing the differences in deposition velocities of daytime and nighttime,
we can infer that the stomatal uptake of corn is the main sink of near-ground O3. |
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