station. Atmospheric moisture is highest in the summer time and
therefore, water vapour abundance and temperature, exerts a
larger influence on the extent of peroxy radical-water complexation.
The Tropical region, such as Mauna Loa characterized by a high
relative humidity, exhibits the highest levels of complexation, as
shown in Fig. 5. RO2.H2O levels at Cape Grim reach a maximum of
7% in summer time (December-January-February) with a lowest of
4% in winter months (June-July-August). It is an attribute of Cape
Grim thought to be due to the arrival of storms originating from the
west (Southern Ocean) (Jimi et al., 2007) which inject high concentrations
of water vapour into the troposphere.