1960~2012年长江三角洲地区雾日与霾日的气候特征及其影响因素

利用1960~2012年长江三角洲地区气象观测资料,对长江三角洲区域雾和霾的时空分布及其影响因素进行了分析.结果表明:长江三角洲地区雾、霾分布不均匀,雾日大值区主要分布在江苏省盐城中部沿海地区、安徽省黄山地区、浙江东部沿海地区,霾日大值区主要分布在以南京、杭州、合肥、衢州为中心的周边城市.时间变化上,城市化水平高的大城市年雾日数在20世纪80年代之前呈增加趋势,之后呈减少趋势;城市化水平低的小城市年雾日数也呈先升后降的趋势,但下降时间滞后于大城市.大城市雾日月平均分布冬季最多,春秋季次之,夏季最少,小城市雾日月平均分布呈双峰型特征,即春季和冬季较多.大城市和小城市年平均霾日数一直呈增加趋势且20世纪90年代之后差距变大.区域气候变化和城市化导致的温度上升,空气污染加剧导致的气溶胶增加,是造成长江三角洲雾日、霾日不同变化特征的原因,但它们之间的相互作用效应复杂,值得深入研究.

Spatial and temporal distribution characteristic of fog days and haze days from 1960~2012 and impact factors over the Yangtze River Delta Region

Spatial and temporal distribution characteristics of Fog days and haze days and connecting factors have been analysed by applying meteorological data from 42 surface weather stations in the Yangtze River Delta region from 1960 to 2012. Results show that:In terms of spatial distribution, the major fog values are distributed in east coastal area of Yancheng city, Huangshan mountain and east coastal area of Zhejiang, while the major haze values are distributed in Nanjing, Hangzhou, Hefei, Quzhou, together with other surrounding cities. In terms of temporal distribution, the annual fog days in large cities has increased since the 1960s but discreased in 1980s; the fog days at small cities has a time lag compared to the evolution at the large cities. Monthly variation of fog days for the large cities appeared with high frequency in winter and spring while less and least in autumn and summer, Monthly variation of fog days for the small cities displayed bimodal trend, with more fog days in spring and winter. Average number of haze days at large cities and small cities depicted a increasing trend, and the differences in the number of haze days for large and small cities had been widening after 1990s. The rising temperature caused by regional climate change and urbanization and the high aerosol abundance caused by heavy air pollution led to the major reason of the different variation characteristics of haze days and fog days in Yangtze River Delta region. However, due to the complicated interaction between each influencing factors, intensive investigation is still required for further study.