Monitoring and Visualization of Aerosol Distribution and Flow Pattern from Main Streets to Residential Quarter

这项研究有两个目的；L)开发一种新的监测系统，能够检测大气中由汽车排放并因其运行而扩散的气溶胶；2)利用该系统开发的观测数据，可视化气溶胶从主要街道到居民区的分布、扩散和流动模式。基于Nd: YAG激光器的激光遥感系统就是为此而开发的。该系统能够进行距离分辨率为10-100m，时间分辨率为几分钟的气溶胶监测。该系统通过步进电机在水平方向上自动扫描，并在半径7km范围内实现全球实时监测。水平观测结果显示，18号公路、406号公路等几条主干道周围存在高浓度气溶胶区。这表明机动车造成的高密度气溶胶从主要街道流向居民区。我们担心对公众健康的影响。垂直观测结果表明，夜间高密度气溶胶在地表附近停留时间较长。机动车在白天大量排放的气溶胶，由于白天对流的作用，其密度在白天较低，在夜间随着大气混合层高度的降低而凝结。一个程序介绍了费尔纳尔德提出的一种新的分析方法，使气溶胶从空气分子中分离成为可能，并应用于观测数据。根据观测值中的信噪比值来评估边界条件是很重要的。为了得到可靠的结果，需要bbb10的值。该程序清晰地显示和可视化了高密度气溶胶的垂直分布。

There were two purposes in this research ; l) development of a new monitoring system capable of aerosol detection in the atmosphere which was exhausted from motorcars and diffused by their running, 2) visualization of the aerosol distribution, diffusion and flow pattern from main streets to residential quarter using the observed data with the system developed.Laser remote sensing system with a Nd : YAG Iaser was newly developed for these purposes. The system was capable of aerosol monitoring with range resolution of 10-100m, time resolution of within several minutes. The system was scanned automatically in the horizontal direction with a stepping motor and enabled a global real time monitoring over a radius of 7km.Results of horizontal observation showed a high density aerosol area surrounded by several main streets such as Route 18 and Route 406, and others. This suggested a flow of the high density aerosol caused by motorcars from the main streets to the residential quarter. We had concern about the effect on public health. Results of vertical observation showed a long time residence of high density aerosol near the suface at night time. It seemed that aerosol exhausted heavily from motorcars during daytime, whose density was low at daytime by the daytime convection, was condensed at nighttime with decreasing a hight of the atmospheric mixed layr.A program introduced a new analysis method given by Fernald, which made a possible to seperate aerosols from air molecules, was applied to the observed data. It was important to evaluate the boundary condition depending on a value of signal to noise ratio in the observation. The value of>10 was required to get reliable results. The vertical distribution of high density aerosol was clearly shown and visualized by the program.