Long-term trend of surface ozone at a regional background station in eastern China 1991–2006: enhanced variability

[摘要] Information about the long-term trends of surface and tropospheric ozone isimportant for assessing the impact of ozone on human health, vegetation, andclimate. Long-term measurements from East Asia, especially China's easternprovinces, are urgently needed to evaluate potential changes of troposphericozone over this economically rapid developing region. In this paper, surfaceozone data from the Linan Regional Background Station in eastern China areanalyzed and results about the long-term trends of surface ozone at thestation are presented. Surface ozone data were collected at Linan during 6periods between August 1991 and July 2006. The seasonality and the long-termchanges of surface ozone at the site are discussed, with focus on changes inthe diurnal variations, the extreme values, and the ozone distribution. Somelong-term trends of surface ozone, e.g. decrease in the averageconcentration, increase in the daily amplitude of the relative diurnalvariations, increase in the monthly highest 5% of the ozoneconcentration, decrease in the monthly lowest 5% of the ozoneconcentration, increase in the frequencies at the high and low ends of theozone distribution have been uncovered by the analysis. All the trendsindicate that the variability of surface ozone has been enhanced. Possiblecauses for the observed trends are discussed. The most likely cause isbelieved to be the increase of NO_x concentration.

[学科分类] 大气科学