研究论文
曹钰,楼晟荣,王茜,黄成,许建明.长三角区域性PM2.5污染的空间分型及其大气环流特征研究[J].环境科学学报,2021,41(5):1665-1679
长三角区域性PM2.5污染的空间分型及其大气环流特征研究
- Spatial classifications on the regional PM2.5 pollution and their dominant synoptic circulations over the Yangtze River Delta region
- 基金项目：国家重点研发计划项目（No.2018YFC0213800）；中国气象局预报员专项项目（No.CMAYBY2019-039）；上海市科委自然基金项目（No.19ZR1462100）；国家自然科学基金项目（No.42005055）
- 作者
- 单位
- 曹钰
- 长三角环境气象预报预警中心, 上海 200030
- 楼晟荣
- 上海市环境科学研究院, 上海 200233
- 王茜
- 上海市环境监测中心(上海长三角区域空气质量预测预报中心), 上海 200235
- 黄成
- 上海市环境科学研究院, 上海 200233
- 许建明
- 长三角环境气象预报预警中心, 上海 200030
- 摘要：本文提出了一种长三角区域性PM2.5污染日的判别方法，以出现5个、8个连片污染城市为检验阈值，分别覆盖了96%和100%的区域污染日.然后利用T-mode斜交旋转分解方法（PCT）对2015—2018年11—2月长三角地区260个区域性PM2.5污染日进行分型，揭示了4种不同的PM2.5的空间分布形态（整体型、西部型、西北型和东北型），其影响范围、持续时间和污染程度存在显著差异.其中，整体型污染受L型高压控制，出现日数最多（139 d）、覆盖范围最广（31个城市）、区域平均浓度最高（104.3 μg·m-3），是影响长三角地区PM2.5环境质量的最重要的污染类型.西部型和西北型分别受东路冷空气、西路冷空气影响，PM2.5分别呈现"西高东低"、"北高南低"的分布形态，前者主要影响安徽大部和浙江北部，后者主要影响安徽北部和江苏西北部.东北型是长三角本地排放在弱气压场和高压中心下混合产生，主要影响江苏大部和上海，基本不受跨区域输送影响.针对不同类型的污染影响范围和程度可以采取差异化的大气污染联防联控措施.
- Abstract：A discrimination method was proposed to identify 260 typical regional PM2.5 pollution days in November, December, January and February during 2015 to 2018 over the Yangtze River Delta (YRD) region. The filtered PM2.5 pollutions day accounted for 96% and 100% of the total days when using the thresholds of more than 5 and 8 adjacent cities reaching the pollution level for validation. Four types of PM2.5 spatial distributions (the total, west, north-west, and north-east type) were identified by the rotated T-mode principal component analysis (PCT) technique, exhibiting large differences in the spatial coverage, temporal duration and PM2.5 levels. Among them, the total (T) type played the most important role in the regional air quality due to the most frequent occurrence (139 d), the broadest spatial coverage (31 cities), and the highest mean concentration (104.3 μg·m-3) of PM2.5 pollution. Moreover, the atmospheric circulation was integrated for each type to elucidate the dominant synoptic patterns and their impacts on the transport of air pollutants. The T type was controlled by the L-shape high pressure. The external pollutants were first blown to YRD region by the northerly wind, and then sedimented, leading to PM2.5 pollutions. The west type and the north-west type were both significantly related to the activities of cold fronts, but having the east and west passage respectively, leading to the distinct spatial distributions of PM2.5 pollution. Different from the above three types, the north-east type resulted from the accumulation of local air pollutants under the control of weak pressure field and high pressure center. To mitigate regional air pollution in the YRD region, different strategies need to be established according to the specific circulation types.
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