2010—2016年上海城区臭氧长时间序列变化特征初探

Preliminary study on the long-term trends of ozone in urban Shanghai from 2010 to 2016

基于2010—2016年上海城区近地面大气臭氧(O_3)的连续在线观测数据,研究了上海城区O_3长时间序列变化规律和污染特征.结果表明,近7年来上海城区O_3污染逐渐凸显,但总体以轻度污染为主,7—8月高温炎热季节以中度污染居多.城区O_3-8 h(臭氧日最大8 h滑动平均)年均增速为3.81μg·m^(-3)·a^(-1),99%和95%分位值增速较快,分别为6.65和4.94μg·m^(-3)·a^(-1);25%、50%和75%分位值的增速在3.06～4.45μg·m^(-3)·a^(-1)之间.春季O_3浓度均值较高,年际变化小;夏季极值较高,且污染超标情况最为突出;秋季O_3浓度次于春、夏季,冬季最低;夏、秋和冬季O_3浓度总体呈上升态势.O_3日变化呈"单峰型",最大值出现在13:00左右,且峰值逐年增加,污染持续时间变长,最小值出现在早晨7:00.城区O_3"周末效应"逐渐减弱.基于KZ过滤器方法的数据分析结果表明,上海城区O_3-8 h长期变化主要受O_3-BF(O_3-8 h的基准组分)影响;O_3-SF(O_3-8 h的天气影响组分)在5—9月对O_3-8 h影响较大,其范围为-98.85～139.60μg·m^(-3).

Continuous measurements were conducted to investigate the long-term trends and characteristics of ozone from 2010 to 2016 in Shanghai urban.The results show that in the past 7 years,the pollution of ozone in the urban area of Shanghai has become more and more serious,and the main factor is mild pollution,with moderate or moderate pollution occurring in July and August.The growth rate of average annual is 3.81μg·m^-3·a^-1,the increasing rates of the O3 concentrations for high percentiles values(99%and 95%)are 6.65μg·m^-3·a^-1 and 4.94μg·m^-3·a^-1 respectively,the growth rates of 25%,50%and 75%were between 3.06 and 4.45μg·m^-3·a^-1.The average value of ozone concentration in spring was the higher and inter-annual changes in small;while the extreme value in summer was higher,and the pollution was the most serious in summer;ozone of autumn was lower than spring and summer,the lowest in winter;ozone showed an increasing trend in summer,autumn and winter in general.Diurnal variation of ozone was"unimodal",the maximum at 13:00 and increased gradually,meanwhile the pollution time became longer,the minimum at 7:00.Weekend effect of ozone is gradually weakened in Shanghai.The data analysis based on the KZ filter method shows that the long-term changes of O3-8 h(maximum 8-hour moving average of ozone days)in Shanghai urban area are mainly affected by O3-BF(O3-8 h Baseline Forcing);O3-SF(O3-8 h Synoptic Forcing)is greater impact on O3-8 h from May to September,the range is-98.85~139.60μg·m^-3.