北京风沙天气的气溶胶特征

利用常规气象观测资料、卫星云图以及1988、1990、1992、1993、1995、2000年等年北京风沙天气期间所采集的气溶胶样品的分析结果,研究了北京的风沙天气分布特征,风沙期间大气污染状况,产生风沙天气的主要原因及沙尘的来源等.初步得出北京的风沙天气主要出现在春季,是造成春季大气污染的重要原因之一;北京春季风沙天气是由沙尘暴、浮尘和扬沙造成,但以扬尘引起的频率为最高,占71.4%;风沙期间大气气溶胶与无风沙时气溶胶的物理化学特征有明显的差异;大气气溶胶的物理化学特征显示出,风沙期间的大气气溶胶主要来源于自然源,以局地尘源为主,人为排放的气溶胶作用相对减弱.

CHARACTERISTICS OF AEROSOLS UNDER DUSTAND SAND WEATHER IN BEIJING

The characteristics of sand and dust weather in Beijing are studied. The distribution of sand and dust weather, the air pollution produced during the sand and dust weather period, the main causes of sand and dust weather, and the sources of sand and dust are investigated through analyzing synoptic climate data, satellite images, air mass trajectories and physical and chemical characteristics of air aerosols. The preliminary conclusions are that the sand and dust weather occurs more frequently in the spring months than other season in Beijing, which is one of the important causes of the air pollution in Beijing. The spring sand and dust weather in Beijing are mainly caused by sandstorms, suspended dust and blowing sand. The proportion resulting from blowing sand is measured up to 71.4%. The physical and chemical characteristics of the air aerosols in the sand and dust weather are obviously different from normal days. The physical and chemical characteristics of the air aerosols demonstrate that during the sand and dust weather the air aerosols mainly come from the local natural source. The role of anthropogenic emission relatively becomes less important.