Perturbation Pressure Variations Deduced from Earthscope's US Array

几十年来，对地面气压扰动的观测一直被用来了解重力波、对流过程和地形-水流相互作用。虽然已经研究了所有尺度上的气压扰动，但在强调通常由局部湍流边界层过程引起的低幅度高频扰动和可以远距离传播并经常导致破坏性大风的大幅度低频扰动之间存在着研究差距。导致影响风能的风坡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2010年开始在NSF赞助的地球镜地震可移动阵列(US阵列)上部署压力传感器的优势。传感器最初位于美国中部，现在开始在两年后部署到美国东部。这项研究的具体目标是：(1)改善大气研究界获取美国阵列获得的气压数据的途径；(2)发展每个观测地点气压扰动的频率和幅度作为位置、季节和一天时间的函数；(3)在局地、中尺度和天气尺度气流的背景下评估水平扰动气压梯度的幅度；(3)评估水平扰动气压梯度的幅度；(4)确定传播压力扰动特征的区域差异；以及(5)检查地形-气流相互作用和热力强迫系统引起的压力扰动。作为这项研究的一部分，当地和区域的气候学、案例研究和合成将被用来检验导致气压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、导管重力波、水风系统等。虽然关于地面气压扰动的产生及其影响已经做了大量工作，但还没有对大区域(在这种情况下，是美国东半部)上广泛的相关时间尺度(几秒到几天)的气压扰动进行任何系统的研究。这项研究以及从研究中获得的知识将适用于世界各地的类似现象。该项目基于对美国阵列项目的熟悉，在数据分析、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：改进对美国阵列压力数据的访问将增加研究人员之间的合作，这些研究人员对这些数据的应用产生的广泛研究感兴趣。对整个社会的好处包括改进对许多不同类型天气情况引起的严重风暴的即时预报和预报，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，并使研究成果能够直接注入犹他大学和其他地方的本科生和研究生课程。该项目包括一名博士后研究员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.