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。严格的辐射和大气流动条件下，阿拉斯加边界层的发展挑战我们的研究在实验和建模方法。在如此严酷的冬季条件下，该项目将进行一次实地密集实验，利用地面、遥感和现场无人驾驶飞机系统记录辐射、湍流、成分和动态。这项研究将促进我们对辐射驱动边界层中发生的物理过程的理解，将观测结果与中尺度/微尺度模拟相结合。研究的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认识，具体而言，该项目侧重于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力状态，以及它们如何在中尺度模型中表现出来。本项目将侧重于以下物理过程：1）在停滞反气旋天气条件下，浅层地面逆温层的建立和破裂; 2）在反气旋和向气旋转变条件下，包括地面逆温层和升高的天气逆温层在内的边界层行为，它们的辐射耦合及其对地面湍流的反馈作用，和3）存在控制混合和输送的浅层冷流时的边界层动态和湍流状态（垂直和水平），导致瞬态边界层状态。实验数据集是独特的，在这个意义上说，目前的表面参数化模型不完全考虑到所示的机制和相互作用的气象框架和条件。这项研究的重要性是突出的需要，以促进了解的化学和微观物质和气体在极地大气的严格条件。空气污染产品的物理和化学变化所固有的是我们能够基于地面或空中观测平台（IGAC-ALPACA实地实验）将污染源与受体联系起来。该项目填补了这一特定的差距，提供关键的观察，中尺度模拟评估和模型验证，以改善模型表示的物理过程，导致极端的边界层状态。同样地，改善对地面风和气温的预报，以及提高极地大气中高分辨率气候产品的质量，都需要更好地代表辐射边界层。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。

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.