Leaf surface wetness measurements on Norway spruce

Held, A.*; Katata, Genki

Leaf surface wetness is an important factor in meteorological, agricultural, and environmental studies of plant-atmosphere exchange processes. 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. Leaf surface wetness was compared with relative humidity and wind speed, two key meteorological controls of leaf surface wetness. Finally, a trial calculation of the multi-layer atmosphere-soil-vegetation model SOLVEG was 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.