Large cities and urban regions are confronted with rising pressure by environmental pollution, impacts of climate change, as well as natural and health hazards. They are characterised by heterogeneous mosaics of urban structures, causing modifications of atmospheric processes on different temporal and spatial scales. Planning authorities need reliable, locally relevant information on urban atmospheric processes, providing fine spatial resolutions in city quarters or street canyons, as well as projections of future climates, specifically downscaled to individual cities. Therefore, building-resolving urban climate models for entire city regions are required as tool for urban development and planning, air quality control, as well as for design of actions for climate change mitigation and adaptation. To date, building-resolving atmospheric models covering entire large cities are mostly missing. The German research programme “Urban Climate Under Change” ([UC]2) aims at developing a new urban climate model, to acquire three-dimensional observational data for model testing and validation, and to test its practicability and usability in collaboration with relevant stakeholders to provide a scientifically sound and practicable instrument to address the above mentioned challenges. This article provides an outline of the collaborative activities of the [UC]2 research programme.

中文翻译：

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变化中的城市气候 [UC]2 – 为整个城市区域开发建筑解析大气模型的国家研究计划

大城市和城市地区面临着环境污染、气候变化影响以及自然和健康危害日益增加的压力。它们的特点是城市结构的异质马赛克，导致不同时间和空间尺度上的大气过程发生变化。规划当局需要关于城市大气过程的可靠的、与当地相关的信息，提供城市街区或街道峡谷的精细空间分辨率，以及未来气候的预测，特别是缩小到单个城市的规模。因此，整个城市区域的建筑解析城市气候模型需要作为城市发展和规划、空气质量控制以及气候变化减缓和适应行动设计的工具。迄今为止，覆盖整个大城市的建筑解析大气模型大多缺失。德国研究计划“变化中的城市气候”（[UC]2）旨在开发新的城市气候模型，获取三维观测数据用于模型测试和验证，并与相关利益相关者合作测试其实用性和可用性提供一种科学合理且切实可行的工具来应对上述挑战。本文概述了 [UC]2 研究计划的合作活动。并与相关利益相关者合作测试其实用性和可用性，以提供一种科学合理且切实可行的工具来应对上述挑战。本文概述了 [UC]2 研究计划的合作活动。并与相关利益相关者合作测试其实用性和可用性，以提供一种科学合理且切实可行的工具来应对上述挑战。本文概述了 [UC]2 研究计划的合作活动。