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Leaf surface wetness measurements on Norway spruce

Andreas Held1, Genki Katata2
1 Atmospheric Chemistry, Universit├Ąt Bayreuth
2 KIT Garmisch-Partenkirchen & Japan Atomic Energy Agency, Japan

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Leaf surface wetness, i.e. a liquid film of water on plant surfaces, is an important factor in meteorological, agricultural, and environmental studies of plant-atmosphere exchange processes.
For example, the deposition of atmospheric trace gases and particles to vegetation depends on the plants' surface properties. Water-soluble gases and particulate compounds are readily taken up in liquid water films, while insoluble compounds stay in the surrounding gas phase. Therefore, liquid water films on plant surfaces can act as a chemical reactor for certain atmospheric species. Despite this important impact on atmospheric chemistry, direct measurements of leaf surface wetness are still scarce.
Here, we present leaf wetness measurements using electrical sensors clipped directly to Norway spruce needles, and deposition estimates of inorganic ions to Norway spruce needles determined by a leaf-washing technique. The measurements were carried out at the Waldstein ecosystem research site of the University of Bayreuth in the Fichtelgebirge mountains. Leaf surface wetness will be compared with relative humidity and wind speed, two key meteorological controls of leaf surface wetness. Finally, numerical simulations of the multi-layer atmosphere-soil-vegetation model SOLVEG will be compared with the observed data.
Overall, leaf surface wetness affects diverse phenomena such as vegetation-atmosphere water exchange or deposition fluxes to vegetation surfaces, which must be further explored in interdisciplinary research projects.

last modified 2014-09-12