But most of
the field measurement data were recorded during years other than
1998, which subsequently complicates their comparison with the
modelled data. The low resolution of our model, which computes
average concentrations over each grid square of dimensions 5
latitude 5 longitude will also tend to lead to an under-prediction
by the model. The measurement data for Hohenpeissenberg is
found to be 5-fold higher than the model results. The Hohenpeissenberg
station is located in a rural agricultural and forested area;
the air arriving at this measurement site due to convective lifting of
the boundary layer is enriched in a number of biogenic VOCs (e.g.
terpenes and isoprene) with surface sources. The polluted air
masses from the East of Hohenpeissenberg (Kaiser et al., 2007)
contribute additional VOC, leading to overall higher production of
RO2. The duration of the field campaigns varies from day to night
and days to months, which causes variation between the model and
measurement data if there is a local source around the monitoring
station. The results of the field studies conducted at Cape Grim
during February deviate from the expected trend as they are 4-fold
lower than those output from the model because in our model
Tasmania sits in the same grid square as Melbourne and is therefore