Abstract:

The concentration monitoring of the Embassy of the United States in China since 2009, the aerosol optical depth of MODIS and the planetary boundary layer data of NCEP were used to analyze the meteorological conditions in the planetary boundary layer of Beijing in recent years. The results show that from 2009 to the summer of 2011 and the summer and winter of 2012, the pollution status of Beijing is serious. In 2013 and 2014, pollution is slightly better. The north wind is benefit to the diffusion of pollutants, and the greater the north wind, the better the diffusion effect. The south wind is benefit to the accumulation of pollutants, and the greater the south wind, the better the accumulation effect. Higher planetary boundary layer results in better diffusion. Greater humidity results in more accumulation. Precipitation has obvious effect on the diffusion of pollutant. Since twenty-first century, these meteorological conditions of Beijing have no obvious interannual variation except the planetary boundary layer height, which is obviously reduced from 2500 m to 1500 m.

Key words: Beijing, PM_2.5, the meteorological conditions in planetary boundary layer

摘要：

利用美国驻中国大使馆2009年以来的PM_2.5浓度监测数据、MODIS 光学厚度数据和NCEP边界层气象要素数据, 对近年来北京地区 PM_2.5 和边界层内气象要素进行分析。结果表明: 2009—2011 年夏、秋季以及 2012 年夏、冬季北京地区 PM_2.5 污染情况较为严重, 2013 和 2014 年污染情况稍有转好; 北风为有利于PM_2.5 扩散的气象条件, 且随着北风增强, 扩散效果更好; 南风为有利于 PM_2.5 堆积的气象条件, 且随着南风增大, 堆积效果略微增加; 边界层高度越高, 越有利于PM_2.5的扩散; 相对湿度越大, 越有利于PM_2.5的堆积; 降水对 PM_2.5 有明显的驱散作用。21 世纪以来, 北京地区的平均边界层高度有明显的降低趋势, 从 2500 m降低到 1500 m 以下, 其他气象要素没有明显的年际变化。

关键词: 北京, PM_2.5, 边界层内气象要素