珠三角区域空气质量空间分布类型和天气背景

SPATIAL DISTRIBUTION TYPES AND WEATHER BACKGROUD OF AIR QUALITY IN THE PEARL RIVER DELTA AREA

基于EOF方法分析2016年珠三角9城市日均AQI指数,前3个空间模态累积方差贡献达90%,得到珠三角区域空气质量3种主要的空间分布类型。整体一致型方差贡献71%,9城市空气质量优劣表现一致,当发生污染时,以静稳天气为背景,佛山、江门、中山和东莞污染较为严重。南北相反型方差贡献12%,夏季南部城市普遍优于北部,冬季则相反,这与珠三角区域南北方向上的主导风向有关。东西相反型方差贡献7%,以地面风场辐散(或辐合)为天气背景,纬向风可能是造成东西部空气质量差异的原因之一。

Daily air quality index data of 9 cities was analyzed by EOF method in the Pearl River Delta（ PRD） area in 2016.Cumulative variance contribution of the first three spatial modes was 90%,indicating three main spatial distribution types of air quality in the PRD area. The variance contribution of regional consistent type reached 71%,with consistent air quality conditions in 9 cities. When pollution occurred,and the PRD area was under stable weather condition,Foshan,Jiangmen,Zhongshan,and Dongguan were more heavily polluted than other cities. The variance contribution of southern and northern anti-phase type accounted for 12%,with air quality better in the south than the north generally in summer,while in winter,because the prevailing wind direction of PRD area turned form south to north or reverse during the year. The variance contribution of eastern and western anti-phase type accounted 7%. It was characterized with a weather background of surface wind divergence or convergence,and the zonal wind could be one of the reasons for this type.