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

城市、湖泊、小岛和风电场是一种与人类有重大关联的陆地表面变化的共同模式的各种表现形式：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）。这种表面对比在1到100公里的多个尺度上扰乱了大气，以前的研究已经确定，这些扰动影响云的形成和降雨，极端的高温和污染，以及风的流动模式等。虽然这些不同的表面特征之前已经被单独研究过，但它们的相似性尚未得到巩固，无法对这类异质表面形成广泛的理解，这阻碍了更好的环境预测所需的理论框架的制定。本项目将调查这类“气象岛”的所有表现形式；这将改善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，这些干扰可能对环境、生态系统服务和更广泛的社会产生不利影响。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高能三维二次环流，并通过这些次级环流扰乱大气动力学。第一个目标是使用这些模拟数据进行降维：总体项目假设是，这类异质性主要由四个非维度参数调节，这些参数足以捕获其所有不同的表现形式。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，从而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，以便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的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.