淮河流域重点城市大气污染源区特征的印痕分析

Footprint Analysis for the Pollutant Sources of Key Cities in the Huaihe River Basin

利用NCEP-fnl再分析气象资料和大气环境监测空气污染指数(API),运用印痕模型,对淮河流域重点城市(郑州、徐州和连云港)的大气污染物源区进行分析,内容包括2010年全年API指数大于300的重污染个例情况以及API大于100的所有污染个例的统计特征。研究结果表明:重污染的出现往往伴随印痕空间分布形态与方向的极大改变,污染发展加重阶段印痕影响区域长度收缩、侧向扩展,污染最重的阶段则对应印痕影响区域和方向的急剧变化,说明重污染过程与天气系统转换期的风速减小、风向改变有密切关系。统计表明:郑州市的潜在污染影响源区主要分布在偏西和西北方向,春季西北方向的影响最显著;徐州市的潜在污染影响源区主要为西南方向,秋季最显著;连云港的潜在污染源区主要为西南和偏西方向,西南方向的影响在秋季最显著。

Based on NCEP-fnl reanalysis data and the air pollution index data of Zhengzhou, Xuzhou and Lianyungang in 2010, the footprint model is used to analyze the potential air pollutant source of those key cities in the Huaihe River Basin. Heavy air pollution episodes in which API is greater than 300 are analyzed, and episodes in which API is greater than 100 are used for statistical analysis. The results illustrate that heavy air pollution episode is often accompanied with great changes in the spatial distribution and the direction of the footprint, and the most polluted stage corresponds to dramatic changes in the affected area and direction of footprint, suggesting that heavy air pollution has close relationship with decrease of wind speed in weather system conversion period. Statistics show that the potential pollution source areas of Zhengzhou are mainly distributed in the west and northwest, and source areas in northwest have the largest effect in spring; the potential pollution source areas of Xuzhou are mainly distributed in the southwest, especially in autumn; the potential pollution source areas of Lianyungang are mainly distributed in the southwest and west, and source areas in southwest have the largest effect in autumn.