ASSURE: Across-Scale processeS in URban Environments

气候变化的局部和全球后果（城市热岛增强，环境条件恶化）影响到世界上大多数城市人口，但直到最近，城市才在天气预报模型中得到反映，尽管很粗糙。要管理和发展可持续、有复原力和健康的城市，就需要改进跨社区影响尺度的预报和观测，而下一代天气预报模型需要解决这些问题。ASSURE解决了关键问题，即哪些过程需要参数化，哪些需要解决，以捕捉城市在空间和时间上的异质性。我们将通过结合现场观测、高分辨率数值模拟和风洞实验的结果，促进对更大规模城市气象和扩散模型的新方法和参数化的理解。实地工作和建模将集中在布里斯托尔，因为它的自然地理提供了适当的高水平的复杂性，并允许整个城市的方法。由于中型城市是温室气体的主要来源，而且人口众多，因此机构能够提供这种规模城市的天气和气候变化预测是至关重要的，因为它们需要这些信息来管理和提供服务。ASSURE将包括理想化的模拟和理论分析，以确保通用适用性。ASSURE的目标是：*了解城市异质性的来源（物理环境、建筑和社区的布局、人类活动）如何结合起来在空间和时间上影响城市氛围。*量化不同尺度（街道到社区、城市和城市以外）的城市异质性对流量、温度、湿度和空气质量控制过程的影响，并确定这些过程如何相互作用。*发展一个理论框架，以降低复杂性捕获关键过程和反馈，以帮助中尺度和更大的模型参数化。*告知具有中尺度能力并用于决策过程（例如综合城市服务）的当前天气和气候模式的发展重点。ASSURE高保真模拟和精心设计的实验将使我们能够探索城市异质性在孤立和组合配置中的含义；解释和整合现场观测（如三维气象和城市尺度示踪剂色散实验）；整合不同的方法来理解不同尺度过程模型中不确定性的大小、来源和地理范围；综合新知识进行理论分析；开发反映这种分析的算法。ASSURE的新颖之处是模拟解决与中尺度模型相关的街道到城市尺度的特征；捕获城市边界层和冠层垂直和水平变化的实地观测，包括新型多源气体示踪剂实验；以及跨越大气稳定性和模型分辨率的风洞模拟。将获得关于建筑形态（或形式）、当地地形和人类活动（例如废热和AQ排放）变化的新见解。ASSURE将产生详细的数据集；深入了解所涉及的大气过程的各个尺度；高保真多尺度城市建模工具；考虑多尺度效应的理论模型；改进当前中尺度模式技能的评估，以及从业人员用于探索城市形态和功能变化时未来城市情景的数据。我们将与本地及国际组织和公司合作，确保项目能惠及更广泛的社会。它们包括：雅文父母与儿童纵向研究、CERC、COWI、ECMWF、气象局、代尔夫特理工大学、斯坦福大学、汉诺威大学、RWDI、萨里传感器和UKCRIC。

Local and global consequences of climate change (enhanced urban heat islands, worsening environmental conditions) affect most of the world's urban population, but only recently have cities been represented, albeit crudely, in weather forecast models. To manage and develop sustainable, resilient and healthy cities requires improved forecasting and observations that cross neighbourhood-influenced scales which the next generation weather forecast models need to resolve. ASSURE addresses the critical issue of which processes need to be parameterised, and which resolved, to capture urban heterogeneity in space and time.We will advance understanding to develop new approaches and parameterisations for larger-scale urban meteorological and dispersion models by combining the results of field observations, high-resolution numerical simulations and wind tunnel experiments. Field work and modelling will focus on Bristol, as its physical geography provides suitably high levels of complexity and allows whole-city approaches. With mid-sized cities being large sources of greenhouse gases, and where large numbers of people live, it is critical agencies can provide predictions of weather and climate variability across cities of this scale as they need this information to manage and provide their services. ASSURE will include idealised simulations and theoretical analyses to ensure generic applicability.The ASSURE objectives are:* To understand how sources of urban heterogeneity (physical setting, layout of buildings and neighbourhoods, human activities) combine to influence the urban atmosphere in space and time.* To quantify effects of urban heterogeneity at different scales (street to neighbourhood, to city and beyond) on flow, temperature, moisture and air quality controlling processes and to determine how these processes interact.* To develop a theoretical framework that captures key processes and feedbacks with reduced complexity to aid mesoscale and larger model parameterisations.* To inform the development priorities of current weather and climate models that have meso-scale capabilities and are used in decision-making processes (e.g. integrated urban services).The ASSURE high-fidelity simulations and carefully designed experiments will allow us to explore implications of urban heterogeneity in isolated and combined configurations; interpret and integrate field observations (e.g. 3D meteorological and city-scale tracer dispersion experiments); integrate different approaches to understand the magnitude, source, and geographical extent of uncertainties in process models at different scales; synthesize the new knowledge to conduct theoretical analyses; develop algorithms reflecting this analysis.Novel in ASSURE are simulations resolving street to city-scale features that are linked to mesoscale models; field observations capturing vertical and horizontal variations in the urban boundary- and canopy-layers, including novel multi-source gas tracer experiments; and wind tunnel simulations across atmospheric stabilities and model resolution. New insights will be gained on the role of variations in the building morphology (or form), local topography, and human activities (e.g. waste heat, and AQ emissions).ASSURE will produce detailed datasets; in-depth understanding across the scale of atmospheric processes involved; high-fidelity multiscale urban modelling tools; theoretical models taking account of multiscale effects; improved assessment of current meso-scale model skill and the data used by practitioners to explore future urban scenarios as city form and function change.We will work with local and international organisations and companies to ensure the project benefits a broad range of society. They include: Avon Longitudinal Study of Parents and Children, CERC, COWI, ECMWF, Met Office, Delft University of Technology, Stanford University, University Hannover, RWDI, Surrey Sensors and UKCRIC.