广东省臭氧污染天气型及其变化特征

结合地面观测资料、再分析数据和客观天气分型方法SOM,分季节、分区域诊断和分析2015~2020年广东省O₃污染天气型及其变化特征.结果表明,2015~2019年广东省O₃污染逐年上升,其中2017~2019年上升较为明显,2020年则明显下降,气象条件和污染物排放的变化均对O₃污染的变化起到重要作用.2017~2020年广东省干季O₃浓度接近或超过湿季O₃浓度,干季污染城数亦接近湿季.弱冷高压脊天气型是影响广东省O₃污染的主导天气型,6a期间共造成526个污染城数.干季和湿季O₃污染的主导天气型分别为弱冷高压脊和台风外围,干季弱冷高压脊天气型污染天数占比呈明显上升趋势,2019~2020年超过湿季台风外围天气型成为影响O₃污染最主要的天气型.在弱冷高压脊天气型下,影响四大区域O₃污染的外来源输送路径主要有东北路和沿海路,湿季珠三角台风外围和粤北变性高压脊天气型下,区域O₃污染则受本地排放影响较大.

Ozone pollution synoptic patterns and their variation characteristics in Guangdong Province

Based on the surface observation data, reanalysis data as well as the SOM objective classification method, ozone pollution synoptic patterns and their variation characteristics in Guangdong (GD) during 2015~2020 were diagnosed and analyzed by different seasons and regions. The ozone pollution kept an upward tendency year by year from 2015 to 2019, with an impressive increase from 2017 to 2019 but a dramatic decrease in 2020. Changes in meteorological conditions and pollutant emissions played an important role in the variation of O₃ pollution. The ozone concentration in dry season was close to or higher than that in wet season, and the number of polluted cities during dry season was also close to wet season. Weak cold high ridge (HR) was the dominant synoptic pattern affecting the ozone pollution, which caused 526cities over standard during 6years. The dominant synoptic patterns of ozone pollution in GD were HR and typhoon periphery (TP) in dry and wet season, respectively. The proportion of pollution days under the control of HR in dry season raised obviously, which surpassed TP in wet season and became the most important weather type affecting ozone pollution. Under the control of HR, the transport paths of ozone in four regions mainly included northeast path and coastal path. Regional ozone pollution in PRD and North-GD were greatly affected by local emissions under the control of TP and DR in wet season, respectively.