ASSURE: Across-Scale processeS in URban Environments

气候变化的局部和全球后果(城市热岛加剧、环境状况恶化)影响着世界上大多数城市人口，但直到最近，城市才出现在天气预报模型中，尽管是粗略的。要管理和发展可持续、有弹性和健康的城市，需要改进预报和观测，跨越受邻里影响的尺度，这是下一代天气预报模型需要解决的问题。ASSURE解决了哪些过程需要参数化以及哪些过程需要解决的关键问题，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，增进对更大规模城市气象和扩散模式的新方法和参数化的理解。现场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。由于中等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异性预测至关重要，因为它们需要这些信息来管理和提供服务。Assue将包括理想化的模拟和理论分析，以确保一般性应用。Assured的目标是：*了解城市异质性的来源(物理环境、建筑物和社区的布局、人类活动)如何组合在一起，在空间和时间上影响城市大气。*量化不同尺度上的城市异质性(街道到邻里、城市和其他)对流量、温度的影响。*开发一个理论框架，以更低的复杂性捕捉关键过程和反馈，以帮助中尺度和更大的模式参数化。*为当前具有中尺度能力并用于决策过程(例如综合城市服务)的天气和气候模式的发展重点提供信息。确保高保真模拟和精心设计的实验将使我们能够探索孤立和组合结构中城市异质性的影响；解释和集成现场观测(例如，3D气象和城市尺度示踪剂扩散实验)；整合不同方法以了解不同尺度过程模式中不确定性的大小、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。Assue中的创新是模拟解决与中尺度模式相关联的街道到城市尺度的特征；现场观测捕捉城市边界和冠层的垂直和水平变化，包括新颖的多源气体示踪剂实验；以及跨大气稳定性和模型分辨率的风洞模拟。ASSURE将在建筑形态(或形式)、当地地形和人类活动(例如余热和AQ排放)变化的作用方面获得新的见解。ASSURE将产生详细的数据集；对所涉及的大气过程规模的深入了解；高保真多尺度城市建模工具；考虑多尺度影响的理论模型；改进对当前中尺度模型技能的评估，以及从业者在探索未来城市形态和功能变化时所使用的数据。我们将与本地和国际组织和公司合作，确保该项目造福于广泛的社会。它们包括：雅芳父母和子女纵向研究、CERC、COWI、ECMWF、Met Office、代尔夫特科技大学、斯坦福大学、汉诺威大学、RWDI、Surrey Sensors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.