Collaborative Research: Surface Boundary Layer Characterization in Urban Areas

城市地区的大气边界层（最接近地面的一层）的特性比大多数农村地区更难描述，因为建筑物存在的障碍物是可变的，难以统计表征，并且足够大，可以延伸到边界层中很长一段距离。例如，预测危险物质的释放将如何在城市环境中扩散，依赖于对空气运动中湍流波动的准确描述，而这种描述在城市中尤其困难。最近的几个综合实验收集了测量数据，以描述城市边界层的特征，但这些测量数据还没有被全面分析或作为一个整体。该项目将使用一套模型和现有的数据集来研究城市边界层湍流的一般特征，并将研究这些特征与无障碍农村地区边界层特征的关系。研究结果将用于制定城市地表对城市边界层的影响的表示方法或参数化方法，这些参数化方法将被纳入扩散模型。然后，改进和测试的模型将能够提供城市地区分散的测试预测。预期的结果是提高预测危险排放或其他城市污染源将如何影响城市人口的能力。

The properties of the atmospheric boundary layer (the layer closest to the surface) are much more difficult to describe in urban areas than in most rural areas because the buildings present obstacles that are variable, hard to characterize statistically, and large enough to extend a significant distance into the boundary layer. Prediction of how a release of a hazardous material will disperse in an urban setting, for example, relies on accurate characterization of turbulent fluctuations in the air motions, and such characterization is particularly difficult within cities. Several recent comprehensive experiments have collected measurements with which to characterize the urban boundary layer, but those measurements have not been analyzed comprehensively or as an ensemble. This project will use a set of models and those existing data sets to develop generalized characteristics of turbulence in the urban boundary layer, and it will examine how those characteristics relate to those of the boundary layer in unobstructed rural areas. The results will be used to develop ways of representing or parameterizing the effects of the urban surface on the urban boundary layer, and those parameterizations will be incorporated into dispersion models. The improved and tested models will then be able to provide tested predictions of dispersion in urban areas. The expected result is improved ability to predict how hazardous releases or other sources of urban pollution will affect the populations of cities.