Boundary-Layers of the Cold and Dark Atmospheres

该奖项旨在研究阿拉斯加极端冬季寒冷和黑暗大气中的大气边界层。阿拉斯加边界层发展的严格辐射和大气流动条件对我们的实验和建模方法的研究提出了挑战。在如此恶劣的冬季条件下，该项目将进行现场密集实验，利用地面、遥感和现场无人机系统记录辐射、湍流、成分和动力学。该研究将结合观测数据与中尺度/微观尺度建模，加深我们对辐射驱动边界层中发生的物理过程的理解。研究影响旨在提高对冬季极地地区空气污染、气象预报和区域气候产品的了解。具体来说，该项目的重点是了解突出的地表辐射冷却、地表不均匀性、大气成分和热力学如何导致特定的边界层湍流和动态状态，以及它们如何在中尺度模型中表示。该项目将重点研究以下物理过程：1）停滞反气旋天气条件下浅层地表逆温层的形成和分解；2）反气旋和过渡到气旋条件期间的边界层行为，包括地表逆温层和升高的天气逆温层，它们的辐射耦合及其对地表湍流的反馈效应；3）边界层动态和湍流状态（垂直和湍流）水平）在存在控制混合和传输的浅冷流的情况下导致瞬态边界层状态。实验数据集的独特之处在于，模型中当前的表面参数化并未完全考虑气象框架和条件中的指示机制和相互作用。这项研究的重要性在于需要加深对极地大气严格条件下颗粒物和气体的化学和微观物理的了解。空气污染产物物理和化学转化的本质是我们能够基于地面或机载观测平台（IGAC-ALPACA 现场实验）将污染源与受体连接起来。该项目填补了这一特定空白，提供关键观测、中尺度建模评估和模型验证，以改进导致极端边界层状态的物理过程的模型表示。同样，改善地表风和气温的预报以及推进极地大气中的高分辨率气候产品需要更好地表示辐射边界层。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。

This award is to investigate atmospheric boundary layers in the cold and dark atmospheres of the extreme Alaskan winters. The stringent radiation and atmospheric flow conditions in which the Alaskan boundary layer develops challenge our research in both experimental and modeling approaches. In such harsh winter conditions, the project will conduct a field intensive experiment to document radiation, turbulence, composition and dynamics using surface, remote sensing and in-situ unmanned aircraft systems. The research will advance our understanding of physical processes taking place in radiative-driven boundary layers combining the set of observations with mesoscale/microscale modeling. Research impacts are geared towards improving understanding of air pollution, meteorological forecasting and regional climate products in polar regions during winters.In specific, the project focuses on understanding how outstanding surface radiative cooling, surface inhomogeneity, atmospheric composition and thermodynamics result in specific boundary-layer turbulent and dynamic states and how they are represented in mesoscale models. This project will focus on the following physical processes: 1) the buildup and breakup of shallow-stratified surface-based temperature inversion layers during stagnant anticyclone synoptic conditions, 2) the boundary-layer behavior including surface-based temperature inversion layer and elevated synoptic temperature inversion layers during anticyclone and transitions to cyclone conditions, their radiative coupling and their feedback effects on the surface turbulence, and 3) the boundary-layer dynamic and turbulent regimes (vertical and horizontal) in the presence of shallow cold flows controlling mixing and transport resulting on transient boundary-layer states. The experimental datasets are unique in the sense that current surface parameterizations in models do not fully account for the indicated mechanisms and interactions in the meteorological framework and conditions. The importance of this research is highlighted by the need to advance understanding of the chemistry and microphysics of particulate matter and gases in the stringent conditions of the polar atmospheres. Inherent to the physical and chemical transformations of air pollution products is our ability to connect sources to receptors based on ground based or airborne observational platforms (IGAC-ALPACA field experiment). This project fills this specific gap providing critical observations, mesoscale modeling assessment and model validation to improve model representation of physical processes leading to extreme boundary-layer states. Similarly, improving forecasting of surface winds and air temperatures and advancing high resolution climate products in polar atmospheres requires a better representation of radiative boundary-layers.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.