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

从主要街道到住宅区的气溶胶分布和流动模式的监测和可视化

基本信息

批准号：
04650494
负责人：
SAITO Yasunori
金额：
$ 1.15万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

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.

本研究有两个目的：1）开发一种新的监测系统，能够监测汽车排放的空气中的气溶胶，并通过它们的运行扩散; 2）使用所开发的系统的观测数据可视化气溶胶的分布，扩散和从主要街道到居民区的流型。YAG激光器就是为此而研制的。该系统能够监测气溶胶，距离分辨率为10- 100米，时间分辨率在几分钟内。该系统采用步进电机进行水平方向的自动扫描，实现了对半径7 km范围内的全球真实的实时监测，水平方向的观测结果显示，在18号线、406号线等几条主要街道的包围下，形成了一个高浓度气溶胶区。这表明机动车造成的高密度气溶胶从主要街道流向住宅区。我们担心对公众健康的影响。垂直观测结果表明，夜间高浓度气溶胶在近地面有较长的停留时间。结果表明，白天汽车尾气排放的气溶胶，由于白天对流的影响，白天浓度很低，到了夜间，随着混合层高度的降低，气溶胶浓度逐渐降低，从而使气溶胶浓度降低。重要的是根据观测中的信噪比值来评估边界条件。需要>10的值以获得可靠的结果。该程序能直观地显示高浓度气溶胶的垂直分布。