大气气溶胶等效吸收的研究

Analysis of effective absorption for atmospheric aerosol

以强吸收性的煤烟气溶胶为例,分析了其等效吸收系数与反映粒子分布的荣格指数的关系,指出随荣格指数的增大,吸收系数呈现出先减小后增大的"U"形结构。对同一成分的气溶胶来说,小粒子的容热能力高于大粒子,随着大粒子的增多,延迟时间逐渐缩短。以光纤式迈克尔逊干涉的简易平台为基础,考察了镜面反射光经准直器端面的透射光和准直器端面反射光所形成的干涉光,在1.064μm近红外平行光束垂直照射下的相位变化,利用相位变化量和等效吸收的关系,获取了晴天、雾天、纸张燃烧的薄烟雾及浓烟雾的大气气溶胶等效吸收的发展过程,测量灵敏度达到10-6m-1,分析了环境温度渐变引起的迈克尔逊干涉信号基线的飘移,为气溶胶吸收过程的详细研究和吸收系数的实际测量提供了试验基础。

The black carbon, which absorbs light intensively, was selected for analysis of relation between effective absorption and Junge index. With increase of Junge index, the absorption coefficient numbers of black carbon firstly descended then ascended, somewhat liked ＆quot;U＆quot;. For aerosol from the same source, the saving heat capacity of small particles was stronger than large ones. When content of large particles increased gradually, delay time droped correspondingly. Based on optical fiber Michelson interference, transmitting light of reflected light by mirror interfered with reflected light by inner surface of collimator. Phase changed when the interfering light path was illuminated by 1.064μm parallel light. It was recorded that effective absorption of aerosol from sunshine, fog, thin and dense smoke from burned paper using relation between phase variation and effective absorption coefficient, and corresponding sensitivity was 10-6 m-1. The baseline of signal always drifted slowly since environment temperature nearly changed all the time. The foundation was shown for research of absorption process and measurement of absorption coefficient.