东亚夏季风对中国东部臭氧输送过程的影响

Influence of East Asian summer monsoon on ozone transport in eastern China

利用2015—2019年中国东部20个省份222个城市的地面O 3观测数据和全球再分析风场数据,研究了中国东部地区O 3的时空分布特征,以及在亚洲夏季风背景下污染上风方O 3光化学输送对下风方O 3质量浓度季节变化的影响。结果表明:中国东部地区O 3质量浓度夏季高、冬季低,O 3质量浓度按照东南、华东、东北、华北的顺序依次升高,位于中高纬度的华北、东北地区明显高于位于中低纬度的华东、华南地区。不同城市、不同季节O 3质量浓度日变化形态具有较好的一致性,都表现为夜晚低、清晨逐渐升高、下午至黄昏达到最大的单周期变化形态,具有典型的光化学控制特征。春季,亚洲夏季风开始影响中国东部地区,华东、华北、东北地区为大范围的O 3高值区;夏季,亚洲夏季风将O 3及其前体物由纬度较低的华南、华东地区向纬度较高的华北、东北地区不断输送和累积,并在夏季强紫外辐射作用下发生光化学反应,导致夏季华北、东北地区的O 3污染。

Based on the surface ozone observation data from 222 cities of 20 provinces in eastern China and the global reanalysis wind data from 2015 and 2019,this paper investigated the spatial-temporal distribution characteristics of ozone in eastern China and evaluated the influence of ozone photochemical transport in the upwind on seasonal variation of ozone mass concentration in the downwind under the background of Asian summer monsoon (ASM).Results show that the ozone mass concentration in eastern China is higher in summer and lower in winter,and increases in the order of Southeast,East,Northeast and North China.The ozone mass concentration in North China and Northeast China at middle and high latitudes is significantly higher than that in East China and South China at middle and low latitudes.Diurnal variations of ozone mass concentration exhibit similar single-period patterns that remain low at night,gradually increasing in the morning and reaching peak during afternoon and twilight in different cities and seasons,showing typical photochemical controlling characteristics.In spring,ASM starts to influence eastern China and causes a large area of high ozone mass concentration in East,North and Northeast China.In summer,ASM continuously transports and accumulates ozone and its precursors from South China and East China with lower latitude to North China and Northeast China with higher latitude,and photochemical reaction occurs under the action of summer strong ultraviolet radiation,leading to summer ozone pollution in North China and Northeast China.