CMG: Multiscale Modeling of Urban Atmospheres in a Changing Climate

该项目将开发模型来模拟城市大气及其与环境气候和大气环流的相互作用，发生在比城市大得多的空间尺度上。该研究将考虑大尺度大气条件对城市尺度天气和气候的小尺度影响，以及城市对周边地区的大尺度影响。高级影响将在各种空间尺度上进行研究，从城市热岛对城市下风乡村的影响到所有城市地区对全球气候的总体影响。在低尺度影响的情况下，目标是开发明确代表城市景观的模型，包括铺砌和建造的城市表面的热、水文和辐射特性，以及“街道峡谷”对风施加的表面阻力。城市效应将通过创建嵌套模式系统来模拟，其中代表城市地区的微尺度模式被纳入代表更大区域的中尺度模式，中尺度模式可能进一步纳入全球模式。对城市区域高档效应的研究将发展通过“参数化”来表示城市区域的策略，其中城市景观的净效应以相对粗糙的分辨率在全球模型中以计算易于处理的方式近似。本项目开发的建模能力将直接有利于决策者解决与城市污染、人类舒适度和气候变化对城市地区的影响有关的问题。该项目还将训练研究生和早期职业科学家进行复杂城市系统的跨学科计算研究，并对其研究结果进行政策讨论。

This project will develop models to simulate the urban atmosphere and its interaction with ambient climate and atmospheric circulation occurring on spatial scales which are much larger than cities. The research will consider both the downscale influence of large-scale atmospheric conditions on urban-scale weather and climate, and the upscale influences of cities on the regions surrounding them. Upscale influences will be studied on a variety of spatial scales, from the effect of urban heat islands on the countryside downwind of a city to the aggregate effect of all urban areas on global climate. In the case of downscale influences, the goal is to develop models which explicitly represent the urban landscape, including the thermal, hydrological, and radiative properties of paved and built urban surfaces, and the surface drag exerted on the wind by "street canyons". Urban effects will be simulated by creating nested modeling systems, in which microscale models to represent urban areas are incorporated into mesoscale models which represent larger regions, which may be further incorporated into global models. Research on the upscale effects of urban areas will develop strategies to represent urban areas through "parameterizations", in which the net effects of urban landscapes are approximated in computationally tractable ways in global models with relatively coarse resolution.The modeling capability developed in this project will directly benefit decision makers addressing issues relating to urban pollution, human comfort, and the effects of climate change on urban areas. The project will also train graduate students and early career scientists to undertake interdisciplinary computational studies of complex urban systems and conduct policy discussions of the results of their research.