Perturbation Pressure Variations Deduced from Earthscope's US Array

几十年来，对地表压力扰动的观测已经被用来理解重力波、对流过程和地形流相互作用。虽然已经研究了所有尺度上的压力扰动，但在强调通常由局部湍流边界层过程引起的低振幅、高频扰动和可以传播很远距离并经常导致破坏性风的大振幅、低频扰动之间存在研究差距。导致影响风能的风坡道的压力扰动和压力梯度往往介于这两个极端之间。这项研究将利用从2010年开始部署的压力传感器，这些传感器将安装在由美国国家科学基金会资助的地球范围地震可移动阵列（US Array）上。这些传感器最初部署在美国中部，两年后开始部署到美国东部。这些采样间隔为1hz的400个站点的压力数据将用于记录从秒到天的时间尺度上的压力扰动，以及在大于150km的空间尺度上这种扰动的空间梯度和波状特征。本研究的具体目标是：(1)改善大气研究界对美国阵列获得的压力数据的获取；(2)根据地点、季节和时间的函数，在每个观测地点发展气压扰动的频率和幅度的气候学；(3)评估局地、中尺度和天气尺度流动背景下水平扰动压力梯度的幅值；(4)确定传播压力扰动特征的区域差异；(5)检查由地形流相互作用和热强迫系统引起的压力扰动。作为本研究的一部分，本地和区域气候学、案例研究和合成材料将用于检查导致压力扰动的许多物理过程的相互作用，即太阳潮汐、山流相互作用、对流系统、管道重力波、水风系统等。这项研究可能会促进对导致大气质量再分配的众多物理过程的认识和理解。虽然对地表压力扰动是如何产生及其影响进行了大量的研究，但对大区域（在本例中为美国东半部）的大范围相关时间尺度（秒到天）上的压力扰动还没有任何系统的研究。这项研究和从研究中获得的知识将适用于世界各地的类似现象。该项目基于对美国Array项目的熟悉，数据分析、挖掘和可视化方面的计算机科学专业知识，以及在统计分析、数据同化、水风系统和山区边界层过程方面的先前研究。更广泛的影响：改善对美国阵列压力数据的访问将导致对这些数据应用产生的广泛研究感兴趣的研究人员之间的合作增加。对整个社会的好处包括改进临近预报和预报由许多不同类型的天气情况引起的强风暴，以及更好地利用风能资源。首席PI的研究和教学活动密切相关，能够将研究成果直接注入犹他大学和其他地方的本科和研究生课程。该项目需要一名博士后和一名博士生的支持和指导。

Observations of surface pressure perturbations have been used for decades to understand gravity waves, convective processes, and terrain-flow interactions. While pressure perturbations on all scales have been studied, there is a research gap between the emphasis on low amplitude, high frequency perturbations arising typically from local turbulent boundary layer processes and large amplitude, lower frequency ones that can propagate over large distances and often lead to damaging winds. The pressure perturbations and pressure gradients leading to wind ramps that affect wind energy tend to fall between these two extremes.This research will take advantage of the deployment beginning in 2010 of pressure sensors on the NSF sponsored Earthscope seismic Transportable Array (US Array). The sensors were initially in the central United States and now beginning to be deployed after two years to the eastern United States. These pressure data at a sampling interval of 1 Hz at ~400 stations will be used to document pressure perturbations on temporal scales from seconds to days and spatial gradients and wave-like characteristics of such perturbations on spatial scales larger than ~150 km.The specific objectives of this study are: (1) Improve access for the atmospheric research community to pressure data acquired by the US Array; (2) Develop climatologies at each observing site of pressure perturbations in terms of frequency and amplitude as a function of location, season, and time of day; (3) Assess the amplitudes of horizontal perturbation pressure gradients in the context of local, mesoscale, and synoptic-scale flows; (4) Determine regional differences in the characteristics of propagating pressure perturbations; and (5) Examine pressure perturbations arising from terrain-flow interactions and thermally forced systems. The local and regional climatologies, case studies, and composites generated as part of this study will be used to examine the interactions of the many physical processes leading to pressure perturbations, i.e., solar tides, mountain-flow interactions, convective systems, ducted gravity waves, water breeze systems, etc.Intellectual Merit: This research may potentially advance knowledge and understanding of the numerous physical processes that lead to the redistribution of mass in the atmosphere. While there has been considerable work on how surface pressure perturbations are generated and their impacts, there has no any systematic study of pressure perturbations over the broad range of relevant temporal scales (seconds to days) over a large region (in this case, the eastern half of the United States). This research and the knowledge gained from the study will be applicable to similar phenomenon around the world. The project builds on familiarity with the US Array project, computer science expertise in data analysis, mining, and visualization, and prior research in statistical analysis, data assimilation, water breeze systems, and boundary-layer processes in mountainous terrain. Broader Impacts: Improved access to the US Array pressure data will lead to increasing collaboration among researchers interested in a broad spectrum of research arising from applications of these data. Benefits for society at large include improved nowcasting and prediction of severe storms arising from many different types of weather situations and better utilizations of wind energy resources. The research and teaching activities of the lead PI are closely related and enable the direct infusion of research findings into undergraduate and graduate courses at the University of Utah and elsewhere. The project involves the support and mentoring of a postdoctoral fellow and a doctoral student.