北京地区一次重污染过程的大尺度天气型分析

对北京2000年11月的一次PM10重污染过程进行分析,以期进行造成PM10质量浓度增量的天气型诊断.结果表明:最不利于污染扩散的气象形势对应着PM10质量浓度增量最大,而不一定是PM10质量浓度达到最高的环境背景场;PM10质量浓度的峰值是逐步累积而成的.提出定义PM10质量浓度从谷值逐日累积到峰值而后重新下降到谷值的状态为一次环境污染过程.根据环境过程与天气型的诊断分析结果认为,PM10质量浓度变化与天气形势演变有较好的对应关系.PM10质量浓度在上升、达到峰值和下降阶段对应的天气形势分别为持续数日的大陆高压均压场、相继出现的低压均压区及锋后的高气压梯度场,其中持续存在的大陆高压均压场是造成重污染浓度累积的主要背景场.

Analysis of Large-Scale Weather Pattern during Heavy Air Pollution Process in Beijing

An analysis of a PM10 heavy pollution process in Beijing in November in 2000 was carried out to diagnose the weather pattern that creates the mass concentration of PM10. The result indicated the most meteorological situation to the PM10 diffusion corresponds to the largest increment of mass concentration of PM10, but not necessarily the highest mass concentration of PM10 . The mass concentration of PM10 peak value is formed by gradually accumulating. It is proposed that the process that PM10 accumulates day after day from the valley value to the peak value and drops again to the valley value is called an environmental pollution process. According to the diagnostic analysis result of environment process with weather pattern, the mass concentration of PM10 change and the synoptic situation evolution have good relationship. The mass concentration of PM10 rise stage, the peak value stage, the drop stage respectively correspond to the mainland high pressure that continues for days, the low pressure that appears one after the other, and the high pressure gradient field after the front, in which the mainland high pressure is the main background field that creates the heavy mass concentration of PM10.