Modeling of Contaminant Dispersion in Complex-Terrain Flows

摘要CTS-9708452 Fernando 该提案已提交给环境地球化学和生物化学（EGB）征求NSF 96-152。 该研究计划的目的是利用实验室实验人员，湍流建模人员，数值分析人员和现场观测人员的互补专业知识，在崎岖（复杂）地形中对气流和污染物扩散进行跨学科研究，包括化学和物理转化。由于垂直混合有限，夜间冷却期间空气汇集，以及缺乏背景中尺度气流冲洗盆地，复杂地形的城市发展容易出现严重的空气污染问题。 影响当地风流的重要地表特征通常在100米的量级，而山谷昼夜空气运动的尺度则在100公里以上。 这些尺度差异给数值模型带来了难题。 此外，在早晨和傍晚地面从冷却到加热的过渡期间，反之亦然（转换或过渡期），风的运动是间歇性的，风速约为每秒一米，因此给实地测量带来了问题。 据了解，现有的预测这些地区的流量和扩散的模型产生不令人满意的结果，特别是在周转期间。 拟议的工作将主要针对复杂地形流动及其验证的一个强大的，通用的，地球化学物理数值模型的发展。将进行实验室和理论研究，以提高对复杂地形、非平衡湍流的基本理解，并开发新的参数化。 对在选定的实地地点每隔10分钟采集的粒子样本进行详细分析，将用于验证湍流参数化和建立气溶胶模型。 一个可用的气象模式将显着修改，以纳入这些新的参数化，包括不稳定的垂直混合和气溶胶输送和化学。 这一新的复杂地形模型将根据现有的和新的实地数据进行测试和校准。 过渡低风期间的风场将通过使用适当比例的实验室复杂地形模型来推导;亚利桑那州凤凰城地区的物理模型将用于此目的。 该数值模型将针对具体地区运行，具有现实的初始和边界条件以及污染源分布，以便对风场、污染物水平、对土壤的影响、室内和室外空气之间的相互作用以及人类接触情况进行业务预测。

ABSTRACT CTS-9708452 FERNANDO This proposal was submitted to the environmental Geochemistry and Biochemistry (EGB) solicitation NSF 96-152. The aim of this research program is to utilize the complementary expertise of laboratory experimentalists, turbulence modelers, numerical analysts and field observationalists to carry out an interdisciplinary study of air flow and pollutant dispersion, including chemical and physical transformations, in rugged (complex) terrain. As a result of restricted vertical mixing, pooling of air during nocturnal cooling and absence of background meso-scale wind flow to flush the basins, urban developments in complex terrain are prone to severe air pollution problems. Often the important surface features which influence the local wind flows are of the order of 100 meters while the valley diurnal air motions are governed by scales of more than 100 km. These scale disparities pose a difficult problem for numerical models. In addition, during morning and evening transitions from cooling to heating of the ground and vice-versa (turnover or transitional periods), wind motions are intermittent with wind speeds of the order of one meter per second, thus posing problems for field measurements. The existing models for the prediction of flow and dispersion in these areas are known to yield unsatisfactory results, especially during turnover periods. The proposed work will be directed primarily toward the development of a robust, general-purpose, geo-chemo-physical numerical model for complex-terrain flows and its validation. Laboratory and theoretical studies will be conducted to improve the fundamental understanding of and develop new parameterizations for complex-terrain, non-equilibrium turbulent flows. Detailed analyses of particle samples taken in selected field sites at 10 minute intervals will be used for the validation of turbulence parameterizations and the development of an aerosol model. An available meteorological model will be significantly m odified to incorporate these new parameterizations, including unsteady vertical mixing and aerosol transport and chemistry. This new complex-terrain model will be tested and calibrated against available and new field data. The wind fields during transitional low-wind periods will be deduced by using properly scaled laboratory complex-terrain models; a physical model of the Phoenix, Arizona area will be used for this purpose. The numerical model will be run for specific areas -- with realistic initial and boundary conditions and source distribution -- for operational forecasting of wind fields, pollutant levels, impacts on soil, interaction between indoor and outdoor air and assessment of human exposure.