| 街谷大气扩散试验研究 |
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| 引用本文： | 俎铁林,王木林,郭相臣,房秀梅.街谷大气扩散试验研究[J].应用气象学报,1987,2(1):67-73. |
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| 作者姓名： | 俎铁林 王木林 郭相臣 房秀梅 |
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| 作者单位： | 1.气象科学研究院大气化学研究室
(俎铁林，王木林，郭相臣)，气象科学研究院大气化学研究室(房秀梅) |
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| 摘 要： | 为研究机动车辆排出的污染物在大气中的扩散规律，在北京做了小风条件下的街谷示踪试验。当楼顶风速u接近或大于1米/秒时，街谷内可形成一稳定的原生涡；u＜0.6米/秒时原生涡将消失。对于楼之间空间较小的街谷，背风面和迎风面的示踪剂浓度平均比值可达8。浓度值沿楼层高度无明显变化；由于快车路旁松墙的阻挡和抬升作用，可能造成沿高度方向楼层中段的浓度偏高。在街谷外，除下风方路面上有一按下风距离的负幂指数衰减的浓度分布外，上风方路面上也有一按较大负幂指数衰减的分布。根据上述试验，给出了用以预测街谷中机动车辆排出的惰性气体污染物的扩散模式；模式中，对原生涡和小尺度湍流，做了分别处理。
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A Study of Atmospheric Diffusion Experiment in City Street Canyons |
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| Affiliation: | (Atmospheric Chemistry Laboratory, AMS) |
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| Abstract: | A series of tracer experiments in city street canyons under light wind was conducted to investigate the atmospheric diffusion of vehicle-generated pollutants. When the roof-level wind speed u was near or larger than 1 m/s, standing primary vortex formed in the street canyon, and as u was less than 0.6 m/s, the primary vortex vanished. The ratio of mean tracer concentrations on leeward side to that on windward side was about 8 for street canyons where the space between buildings was small. The tracer concentrations were near constant along vertical direction of buildings faced to the canyon, but it seems higher in the middle of the building heights than otherwheres, because the tracer plume may be resisted and raised by pine trees beside the lane. It was also found that the tracer concentration decayed with distance in a larger negative exponential order for the upwind direction than that for the downwind direction. According to the experiments mentioned above a practical diffusion model was developed for predicting concentration of inert and vehicle-generated pollutants in the city street canyon. In the model the turbulent diffusion was divided into two kinds of motion: the primary vortex and the microscale turbulence |
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