Collaborative Research: Instabilities, Dynamics, and Energetics accompanying Atmospheric Layering (IDEAL)

在稳定条件下，从极低高度进入平流层及以上的自由大气的垂直结构通常以薄的、强稳定的、非湍流的“薄片”为特征，这些“薄片”被较厚的、较弱分层的、常常是湍流的“层”隔开。自由大气中“片层”(S和L)结构的产生和形态被认为是由大尺度风切变、不同频率的重力波、局部S和L的不稳定动力学、湍流和混合及其相互作用控制的。L结构几十年来一直被认为在光学和无线电波传播以及热量、动量和成分的传输和混合中发挥着重要作用。也有证据表明，这些小尺度流动特征可能对更大尺度的动力学有重要影响，包括伴随着GWS传播到更高高度的不稳定性和动量输送。然而，在理解基本动力学或解决不稳定和湍流的作用、它们之间的相互作用或这些流动对输送和混合的影响方面，进展甚微。特别是，稳定层结中间歇性湍流事件的来源、形态和统计数据，以及它们对环境条件的依赖性仍有待观测定义(如S和L厚度的不稳定特征和统计，湍流结构参数和尺度，以及机械和热能耗散率)。迄今为止，我们对这些动力学缺乏了解，这在很大程度上可以归因于以足够的空间和时间分辨率捕捉相关大气结构和动力学的观测和计算挑战。伴随大气分层的理想、不稳定性、动力学和能量学研究项目将进行地面和现场测量以及相关的建模，以量化这些过程，并提供对S和L在整个分层大气中的动力学和影响的关键见解。Idea将在犹他州的Dugway试验场或怀俄明州的根西营联合训练中心(CG)进行测量，那里已经确定了限制空域。智力优势：将首次使用多个协调的高分辨率现场传感器以及集成的探空雷达剖面仪和无线电探空仪来观测自由对流层中普遍存在的S和L结构的动力学。观测的指导和解释将得到高分辨率数值模拟的帮助，能够识别关键动力学并评估层化湍流、混合和输送的理论和模型。更广泛的影响：更定量地了解S和L在稳定层化大气中的动力学将有助于将它们对输送和混合的影响参数化，并提高与许多研究界相关的预报能力。这些应用包括各种应用，如污染和逃逸排放影响、微气候预测和航空安全。该项目将培训两名研究生，学习最先进的大气科学、航空航天工程和计算流体力学。在这项工作中开发的测量技术和技术将有利于未来的实地研究活动和法规遵从性任务。

The vertical structure of the free atmosphere under stable conditions from very low altitudes into the stratosphere and above is often characterized by thin, strongly stable, non-turbulent "sheets" separated by thicker, more weakly stratified, and often turbulent "layers". The occurrence and morphology of "sheet-and-layer" (S&L) structures in the free atmosphere are believed to be governed by larger-scale wind shears, gravity waves (GWs) at various frequencies, local S&L instability dynamics, turbulence and mixing, and their interactions.S&L structures have been known for several decades to play important roles in optical and radiowave propagation and in transport and mixing of heat, momentum, and constituents. There is also evidence that these small-scale flow features can have important implications for larger-scale dynamics, including instabilities and momentum transport accompanying GWs propagating to higher altitudes. However, little progress has been made in understanding the underlying dynamics or addressing the roles of instabilities and turbulence, the interactions among them, or the consequences of these flows for transport and mixing. In particular, the sources, morphologies, and statistics of intermittent turbulence events in stable stratification, and their dependence on environmental conditions remain to be defined observationally (e.g., instability character and statistics of S&L thicknesses, turbulence structure parameters and scales, and mechanical and thermal energy dissipation rates).Our lack of understanding of these dynamics to date can largely be attributed to observational and computational challenges in capturing the relevant atmospheric structures and dynamics with sufficient spatial and temporal resolution. The research program IDEAL, Instabilities, Dynamics, and Energetics accompanying Atmospheric Layering will conduct ground-based and in-situ measurements and associated modeling combined to quantify these processes and provide key insights into S&L dynamics and effects throughout the stratified atmosphere. The IDEAL will perform measurements either at Dugway Proving Ground (DPG) in Utah or at Camp Guernsey Joint Training Center (CG) in Wyoming, where restricted airspace is already assured.Intellectual Merit:For the first time, the dynamics underlying ubiquitous S&L structures in the free troposphere will be observed with multiple, coordinated, high-resolution, in-situ sensors together with the integrated sounding radar profiler and radiosondes from ~50 m to 4 km. Guidance and interpretation of the observations will be aided by high-resolution DNS, enabling identification of key dynamics and evaluation of theories and models of stratified turbulence, mixing, and transport.Broader Impacts:A more quantitative understanding of S&L dynamics in the stably stratified atmosphere will contribute to parameterization of their implications for transport and mixing and improve predictive capabilities of relevance to many research communities. These include applications as diverse as pollution and fugitive emission impacts, micro-climate forecasting, and aviation safety. The project will train two graduate students in state-of-the-art studies in atmospheric science, aerospace engineering, and computational fluid dynamics. Measurement technologies and techniques developed in this work will benefit future field research campaigns and regulatory compliance mandates.