METEOROLOGICAL MODELING ON HIGH-OZONE DAYS IN PERTH, WESTERN-AUSTRALIA

The West Australian capital city of Perth is located on a coastal plai n between the sea to the west and an escarpment rising to the east. It is;isolated from all other cities or sources of pollution. In this st udy, the meteorological conditions leading to high ozone levels have b een classified according to the dominant weather patterns using both s ynoptic charts and air monitoring data. The data revealed that practic ally all high-ozone days were associated with recirculation of ozone o r its precursors. Meteorological modeling was then performed for the g eneric conditions leading to high ozone in the Perth region. The model ing predicted that recirculation of surface air over the Perth region was common. Both same-day and next-day recirculation of surface air ar e features of the model predictions and are conducive to high ozone le vels. The modeling predicts day-by-day buildup of smog to be a favored occurrence under these synoptic conditions. Other interesting meteoro logical features seen in Perth observations on high-ozone days were al so predicted by the modeling, including stalling sea breezes under som e conditions, hydraulic jump effects over the escarpment, and mesoscal e enhancement of the west coast trough.