2006—2008年秋季广州市重大气污染过程特征研究

利用地面图、高空天气图(850 hPa、500 hPa)以及气象要素对2006—2008年秋季(9—11月)广州市4次典型的大气污染过程进行研究,分析其大气污染过程的特征及其相对应的天气系统、与气象要素之间的关系。结果表明,广州市秋季重大气污染多数发生在:(1)广州受冷空气影响或回暖期,持续小风或出现静风会导致污染物大量积聚,且多出现能见度明显下降;(2)由于偏北风的输送作用,处于下风向的万顷沙站较易出现重大气污染过程,表现出明显的区域性污染输送特征;(3)冷高压脊、回流天气形势、台风外围下沉气流影响期间;(4)近地面层出现逆温层或等温层。

RESEARCH OF THE CHARACTERISTICS OF HEAVY AIR POLLUTION PROCESS IN THE FALL 2006-2008

Using the surface, high-altitude weather maps (850 hPa, 500 hPa) and meteorological elements, 4 typical air pollution processes in Guangzhou in autumn (September to November) from 2006 to 2008 are investigated, and the characteristics of each process in relation with corresponding weather systems as well as the meteorological elements are analyzed. The results are shown as follows. (1) Heavy air pollution in Guangzhou in autumn always occurs when cold air affects or when it is getting warmer, with the wind speed persistently light or calm that leads to accumulation of multiple pollutants; visibility decreases significantly when heavy air pollution happens. (2) As a result of the channeling effect of northerly winds in fall in Guangzhou, Wanqingsha station, located downwind, is likely to experience heavy air pollution processes that show significant characteristics of regional pollution transport. (3) The impact of ridges of cold high pressures, return-flow weather situations, and the outer downward flow of typhoons are also important factors beneficial to the occurrence of heavy pollution in Guangzhou in fall. (4) Heavy air pollution is usually accompanied with the appearance of inversion layers near the surface.