Classification of Meteorological Patterns Associated with the Ozone Categories in Kelowna, British Columbia

Abstract

To develop a highly skillful, semiautomated means of forecasting periods of high ozone concentrations, it is critical to understand how ozone concentrations depend on weather patterns, especially in extreme cases. In this work, the synoptic-scale weather patterns that are optimal for photochemical ozone production in the southern interior region of British Columbia are discerned. Rather than generate meteorological composites for days on which an arbitrary 1-h ozone concentration is exceeded, the authors isolate these days through use of the diurnal-curve space defined by M. Böhm et al. This novel technique defines a set of diurnal ozone patterns to characterize ozone exposure at a location. It is applied to hourly ozone data in Kelowna, British Columbia, for the period 1984?96. Each day in the May?October ozone season was categorized using the Böhm classification. The meteorological data for each group of dates were then aggregated to generate a set of corresponding composite atmospheric patterns. These composite synoptic maps represent the typical meteorological scenarios that lead to the corresponding diurnal ozone curve experienced at Kelowna. Of special interest are the C2 (urban/small) and C4 (urban/medium) categories.