Meteorological Islands: How the Atmosphere Interacts with Large Individual Patches of Heterogeneity

城市、湖泊、小岛和风力发电场是与人类密切相关的陆地表面变化的常见模式的各种表现：它们往往形成一个大的、孤立的斑块，具有与周围环境截然不同的特征(粗糙度、温度、湿度)。这种地表对比度在从1公里到100公里的多个尺度上扰乱了大气层，之前的研究已经确定，这些扰动影响了云的形成和降雨、极端高温和污染以及风流模式等。虽然以前对这些不同的表面特征进行了单独研究，但它们的相似之处尚未得到统一，以促进对这类非均质表面的广泛了解，这阻碍了更好地预测环境所需的理论框架的形成。该项目将研究这种类型的“气象岛屿”的所有表现形式；它将改进这些重要地区附近的天气预报和气候预测模式；并将指导土地利用规划和政策，旨在避免人类对陆地表面的干扰，从而对环境、生态系统服务和社会造成更广泛的不利影响。该项目将使用最先进的湍流模拟方法(大涡模拟)来捕捉这些斑块产生的能量三维次生环流，并通过它扰乱大气动力学。第一个目标是使用这些模拟数据进行降维：最重要的项目假设是，这种异质性主要由四个足以捕捉其所有不同表现的无量纲参数调节。第二个目标是了解粗糙度、温度和湿度的对比如何相互作用，影响这些斑块附近的大气。最后，这些分析将被综合成一个连贯的理论框架，允许在天气和气候模式中更好地参数化这些斑块对大气的未解决影响。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Cities, lakes, small islands, and wind farms are various manifestations of a common pattern of land surface variability of significant relevance to humans: they tend to form a large, isolated patch with very distinct features (roughness, temperature, wetness) from the surroundings. This surface contrast perturbs the atmosphere at multiple scales ranging from 1 to 100 km, and previous research has established that these perturbations impact cloud formation and rainfall, extreme heat and pollution, and wind flow patterns, among others. While these various surface features have been examined individually before, their similarities have not yet been consolidated to develop a broad understanding of this class of heterogeneous surfaces, hindering the formulation of theoretical frameworks that are needed for better environmental prediction. This project will investigate this type of “Meteorological Islands” in all its manifestations; it will result in improved weather forecasting and climate projection models in the vicinity of these important areas; and will guide land use planning and policy aiming to avoid human perturbations to the land surface that can result in adverse impacts on the environment, ecosystems services, and society more broadly.The project will use a state-of-the-science turbulence simulation approach (large eddy simulation) to capture the energetic three-dimensional secondary circulations that these patches generate and through which they perturb atmospheric dynamics. The first goal is to use these simulation data for dimensional reduction: the overarching project hypothesis is that this class of heterogeneity is primarily modulated by four non-dimensional parameters that are sufficient to capture all its various manifestations. The second goal is to understand how the contrast in roughness, temperature, and wetness interact to impact the atmosphere in the vicinity of these patches. Finally, these analyses will be synthesized into a coherent theoretical framework that will allow better parametrization of the unresolved impact of such patches on the atmosphere in weather and climate models.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.