1960~2013年华南地区霾污染的时空变化及其与关键气候因子的关系

利用线性回归、聚类分析及相关分析等统计方法对华南地区57个地面气象站的观测资料进行分析,探究近54年华南地区霾日数的时空变化特征及其气候成因.结果表明,年平均霾日数大值区主要分布在广东珠江三角洲(珠三角)地区和广西中东部.54年来霾日数呈现显著的上升趋势,而2008年后有所下降.霾日数的季节变化表现为冬季最多,其次是秋季和春季,夏季最少.2008年以后春、夏、秋3季霾日数有所下降,而冬季仍维持在较高水平.不同等级霾日数在近54年来均有不同程度的上升,霾污染不仅在日数上有明显的增加趋势,而且污染强度在加强.不同地区霾日数的快速增长时期不一样,污染严重和正常污染地区发生在20世纪90年代,而相对清洁地区发生在2000年以后.另外近10年污染严重和正常污染地区霾日数有所下降,但相对清洁地区仍维持快速的增长趋势.近54年华南地区年降水日数、年平均风速、大风日数和年小风日数等气候因子变化结果致使气溶胶粒子的湿沉降减弱,污染物扩散能力下降,霾天气生成概率增加.

Temporal and spatial characteristics of haze days and their relations with climatic factor during 1960~2013 over South China

This study investigates temporal and spatial variations of haze days and the possible climatic factors in South China during recent 54years. Basic statistical methods are used here based on the observed data from 57meteorological stations, including linear regression, cluster and correlation analysis. The result shows that more haze days occur in the Pearl River Delta (PRD) region of Guangdong and mid-eastern Guangxi. The haze days increase remarkably during the past 54 years and show a decline trend after 2008. Among the four seasons, the heaviest haze pollution happened in winter, follows spring and autumn, and relatively weak in summer. They are also associated with a decrease trend after 2008 except winter. In addition, all of the haze days in different varied-intensity increased obviously during the past 54 years. It is further found that haze pollution in South China increases not only in the number of days, but also the pollution intensity. The rapidly rise time periods of haze days are different in different regions over South China. It occurs in the 1990s over serious pollution and normally pollution regions, but shows after 2000 for the relatively clean regions. Number of haze days over the serious polluted and normal polluted regions has been decreased during recent 10 years, but it remains a rapid increase for the relatively clean areas. Our further analysis suggests that the decreased trends of precipitation days during recent 54 years would factor in reducing the wet-depositing capacity of atmospheric pollutants. Increase of the breeze days, which connects to the decrease of mean wind speed and strong wind days, on the other hand, would also contribute to the reduction of pollutants diffusion capacity and more haze pollution.