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| Titel |
Direct leaf wetness measurements and its numerical analysis using a multi-layer atmosphere-soil-vegetation model at a grassland site in pre-alpine region in Germany |
| VerfasserIn |
Genki Katata, Andreas Held, Matthias Mauder |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096693
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| Publikation (Nr.) |
 EGU/EGU2014-12207.pdf |
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| Zusammenfassung |
| The wetness of plant leaf surfaces (leaf wetness) is important in meteorological, agricultural,
and environmental studies including plant disease management and the deposition process of
atmospheric trace gases and particles. Although many models have been developed to predict
leaf wetness, wetness data directly measured at the leaf surface for model validations are still
limited. In the present study, the leaf wetness was monitored using seven electrical
sensors directly clipped to living leaf surfaces of thin and broad-leaved grasses. The
measurements were carried out at the pre-alpine grassland site in TERestrial ENvironmental
Observatories (TERENO) networks in Germany from September 20 to November 8,
2013. Numerical simulations of a multi-layer atmosphere-SOiL-VEGetation model
(SOLVEG) developed by the authors were carried out for analyzing the data. For
numerical simulations, the additional routine meteorological data of wind speed, air
temperature and humidity, radiation, rainfall, long-wave radiative surface temperature,
surface fluxes, ceilometer backscatter, and canopy or snow depth were used. The
model reproduced well the observed leaf wetness, net radiation, momentum and
heat, water vapor, and CO2 fluxes, surface temperature, and soil temperature and
moisture. In rain-free days, a typical diurnal cycle as a decrease and increase during
the day- and night-time, respectively, was observed in leaf wetness data. The high
wetness level was always monitored under rain, fog, and snowcover conditions. Leaf
wetness was also often high in the early morning due to thawing of leaf surface water
frozen during a cold night. In general, leaf wetness was well correlated with relative
humidity (RH) in condensation process, while it rather depended on wind speed
in evaporation process. The comparisons in RH-wetness relations between leaf
characteristics showed that broad-leaved grasses tended to be wetter than thin grasses. |
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