The influence of turbulent events that
are typically associated with large coherent structures in the
canopy boundary layer (e.g. Finnigan, 2000; Zhu et al., 2007b),
was examined by applying Quadrant–Hole analysis to the
sonic anemometer’s data sets. In particular, the effect of
turbulent events with positive vertical velocity fluctuations,
ejections being the prominent phenomenon, was related to
the fraction of pollen transported upwards from canopy
height. For the 2 days that turbulence data were available,
the analysis showed that during morning hours, periods
with high duration fraction of strong upward motions
(‘‘ejections’’) coincided with those of high pollen concentrations,