• 广州地区秋季PM2.5和臭氧复合污染的观测研究
  • Observation studies on the PM2.5 and O3 complex episodes during autumn in Guangzhou
  • 基金项目:国家重点研发计划(No.2018YFC0213901,2019YFC0214605);国家自然科学基金(No.41775037);广东省气象局科技创新团队项目(GRMCTD202003);广东省重点领域研发计划项目(No.2020B1111360003)
  • 作者
  • 单位
  • 何国文
  • 中国气象局广州热带海洋气象研究所/广东省区域数值天气预报重点实验室;暨南大学质谱仪器与大气环境研究所/广东省大气污染在线源解析系统工程技术研究中心
  • 邓涛
  • 中国气象局广州热带海洋气象研究所/广东省区域数值天气预报重点实验室
  • 欧阳珊珊
  • 暨南大学环境与气候研究院;暨南大学环境与气候研究院
  • 陶丽萍
  • 暨南大学质谱仪器与大气环境研究所/广东省大气污染在线源解析系统工程技术研究中心
  • 李振宁
  • 香港科技大学环境及可持续发展学部,中国香港
  • 吴晟
  • 暨南大学质谱仪器与大气环境研究所/广东省大气污染在线源解析系统工程技术研究中心
  • 张雪
  • 暨南大学质谱仪器与大气环境研究所/广东省大气污染在线源解析系统工程技术研究中心
  • 吴兑
  • 中国气象局广州热带海洋气象研究所/广东省区域数值天气预报重点实验室
  • 摘要:本研究主要利用2019年9-10月广州市海珠湖大气成分观测站地表的气象要素和空气质量参数及垂直的颗粒物激光雷达观测资料,探讨不同PM2.5-O3污染类型对应的气象要素及大气污染物日变化特征、边界层内气溶胶分布特征,并对发生高PM2.5-高O3的成因进行分析。观测期间共出现25天低PM2.5-低O3日(清洁日)、12天低PM2.5-高O3日(污染日Ⅰ)与20天高PM2.5-高O3日(污染日Ⅱ)。对气象要素和污染物特征分析表明,污染日Ⅱ在11:00~16:00的平均气温、相对湿度均超过30℃和低于60%,日均风速与最大JNO2分别为0.88m/s和0.007s-1。污染日Ⅱ与清洁日相比,其对应的气象要素表现为显著的高温低湿特征;与单一的O3污染日相比则表现为略低的光化辐射和较低风速特征。PM2.5和O3浓度日均值分别是清洁日的2.3和1.5倍,且对应着高浓度SO2和NO2、高大气氧化能力与细粒子占比。雷达观测结果表明,清洁日及污染日Ⅰ的气溶胶消光系数较小且主要在0.1~0.2km-1,污染日Ⅱ中则为0.2~0.3km-1且高值在500m以下。午后的气溶胶退偏比较清洁日与污染日Ⅰ的高,具明显的二次气溶胶生成特征。污染日Ⅱ的典型污染过程分析表明边界层演变可直接影响地表污染物分布,在副热带高压与台风外围下沉气流控制下,早上残留层内污染物的垂直向下输送过程对地表污染物浓度的积累有重要影响。
  • Abstract:By using observational data including surface meteorological elements, air quality parameters and the vertical aerosol lidar observation data from Guangzhou Haizhu Lake Atmospheric Composition Station during September to October 2019, the article studied the diurnal cycle of meteorological elements, atmospheric pollutants and the distribution of boundary layer aerosol corresponding to different types of PM2.5-O3 episodes. The causes of high PM2.5-high O3 were further analyzed. A total of 25 days of low PM2.5-low O3 days (Clean Days), 12 days of low PM2.5-high O3 days (Episodic Days Ⅰ) and 20 days of high PM2.5-high O3 days (Episodic Days Ⅱ) were identified during the observation period. The analysis of meteorological elements and atmospheric pollutants showed that on Episodic Days Ⅱ the average temperature (T) and relative humidity (RH) were over 30 ℃ and lower than 60% from 11:00 to 16:00, and the average daily wind speed (WS) and the maximum J(NO2) were 0.88 m·s-1 and 0.007 s-1, respectively. Compared with Clean Days, Episodic Days Ⅱ is represented by high T and low RH. Meanwhile, slightly lower actinic radiation and lower WS can be found in Episodic Days Ⅱ than Episodic Days I. The daily mean PM2.5 and O3 concentration were 2.3 and 1.5 times of those on clean days, corresponding with the high concentration of SO2 and NO2, high atmospheric oxidation capacity and fine particles ratio on Episodic Days Ⅱ. The lidar results showed that the aerosol extinction coefficient of Clean Days and Episodic Days Ⅰ were lower, and mainly in the range of 0.1~0.2 km-1. In Episodic Days Ⅱ, the aerosol extinction coefficients were in the range of 0.2~0.3 km-1 and the maximum value was below 500m. In the afternoon, the aerosol depolarization ratio in Episodic Days II was larger than that of Clean Says and Episodic Days Ⅰ, indicating obvious feature of secondary aerosol generation. The analysis of typical pollution episodes on Episodic Days Ⅱ shows that the boundary layer evolution could directly affect the distribution of surface pollutants. In the context of Western Pacific Subtropical High and typhoon periphery, the downward transport of pollutants inside the residual layer had a significant influence on the accumulation of surface pollutant concentration in the morning.

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