摘要
作为酸雨和细粒子的前体物,SO2对空气质量和人体健康乃至气候与环境的影响十分重要,特别是在不利于扩散的气象条件下,SO2可造成城市短时间严重污染事件。作者以2006年北京325m气象塔15m观测平台SO2观测数据为基础,结合同步气象资料分析研究发现:1)SO2浓度冬季高、夏季低;全年日均值为(22.5±22.1)×10-9,最大日均值能达到113×10-9。日变化呈现双峰型,峰值出现在北京时间08:00和22:00;并且季节差异明显,冬季浓度为夏季的4.5倍,采暖期为非采暖期的3.2倍。2)风向、风速与SO2扩散和输送密切相关,高浓度SO2在东北、东、西方向上出现频率分别为25.8%、13.8%和11.8%;而西北、北方向上的风速越大对SO2清除效果越好。3)利用平均晴空指数划分采暖期阴霾天和晴天,发现阴霾天混合层高度与平均风速仅为(376±204)m和1.1m.s-1,容易造成SO2累积。4)SO2污染过程呈现周期性的局地累积—清除特征,地形、静风和暖低压是造成北京2006年1月一次重污染事件的成因。
As the precursor of acid rain and fine particle, SO2 not only affects air quality and human health, but also does climate and living environment. Especially in poorly diffusive meteorological conditions, there were the short-term serious pollution events of SO2. The concentrations of SO2 and meteorological factors were observed and analyzed continuously from 1 January to 31 December 2006 in the 15-m platform of Beijing 325-m meteorological tower. The results showed that the high SO2 concentrations existed in winter, conversely in summer. The average daily SO2 concentration was （22.5±22.1）×10^-9 , but the maximum could reach 113×10^-9. The diurnal variations showed a very clear cycle with two peaks, which were 0800 LST and 2200 LST. The ratios of the SO2 concentrations were 4. 5 between winter and summer, and 3.2 between heating period and non-heating period. The dispersion of SO2 had close relationship with wind speeds and wind directions. The frequencies of the high SO2 concentrations were 25.8%, 13.8% and 11.8% in the northeast, east and west. But the wind in the north and the northwest took away SO2more clearly, when the wind speeds were higher. According to clearness index to judge haze day and clear day, it showed that the height of the mixed layer and wind speed were 376±204 m and 1.1 m·s^-1, respectively. The mentioned meteorological conditions leaded to the accumulations of SO2 easily. There was the periodical local accumulation-removal character in the polluted processes. Geography, static wind, quasi-static wind, warm low pressure and the advection-diffusion factor play crucial roles in the serious pollution event from January 18 to January 20 2006.
出处
《气候与环境研究》
CSCD
北大核心
2009年第1期69-76,共8页
Climatic and Environmental Research
基金
国家重点基础研究发展规划2007CB407303
国家自然科学杰出青年基金项目40525016
国家高技术研究发展计划2006AA06A301
关键词
SO2
风速
风向
阴霾天
SO2, wind speed, wind direction, haze day
