ANALYSIS AND PREDICTION OF SURFACE O_3 CONCENTRATION AND RELATED METEOROLOGICAL FACTORS IN SUMMERTIME IN URBAN AREA OF SHANGHAI

Observation and analysis of surface ozone concentration was performed in Xujiahui,Shanghai in the summer of 2005.By studying the relationship of ozone concentration with meteorological factors,a simple and practical regressive statistical method was used to forecast hourly maximum ozone concentration.The following conclusions were drawn.(1) Weather condition affects the formation of ozone obviously,which means that the average ozone concentration in sunny days is much higher than that in overcast days and rainy days.(2) The ozone concentration has an obvious diurnal variation with its main peak at 12: 00～14: 00 and valley before sunrise(05: 00～06: 00) and another very small peak between 03: 00～5: 00.All the factors,such as high-pressure system,cloud cover,high radiation,low relative humidity,wind speed,wind direction and high temperature,lead to high concentration of ozone pollution.When the surface and upper-level winds blow from the northwest with low velocity,it is prone to have high concentration of ozone pollution.By using high-ozone-concentration-potentiality-index(HPPI) and wind-direction-index(WDI) and other meteorological factors,a stepwise regression equation was built to give daily forecast of hourly maximum ozone concentrations.