CEDAR: Global and Seasonal Occurrence and Characteristics of Mesospheric Bores

这个奖项是一项实验性的努力，旨在描述地球大气中罕见但强烈的扰动，这种扰动通常是肉眼可见的，即从地平线延伸到地平线的称为气辉的大条带微弱光学发射。这些扰动是大气波，被称为中间层孔。这些波的特征是一个广泛传播的“阶梯状”锋面区域，增强或耗尽气辉跟随一列波。中间层孔具有较大的亮度振幅（通常为10%），并且可以通过中间层-低层热层（MLT）区域输送大量的能量和动量。波浪动力学对MLT和高层大气区域的大尺度温度和环流结构有显著影响。了解MLT区域波效应的全部范围对于获得大气过程的完整物理图像是重要的。这项工作将利用来自8个现有地面光学成像系统的数据，以及一套多诊断仪器和卫星数据，研究MLT区域中间层孔和其他锋面重力波的全球和季节性发生特征。这项工作将：1)对这些波进行全球调查和表征，并使用波士顿大学的全天成像仪网络估计有助于MLT的动量通量；2)利用同址的地面多诊断测量和卫星测量来补充成像仪数据，以充分表征传播环境和重力波传播模式。该奖项反映了美国国家科学基金会的法定使命，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 an experimental effort to characterize rare but strong disturbances in the Earth's atmosphere that are often visible to the naked eye as large bands of faint optical emission called airglow that extend from horizon to horizon. These disturbances are atmospheric waves that are known as mesospheric bores. These waves are characterized by an extensive propagating "step-like" frontal region of enhanced or depleted airglow followed a train of waves. Mesospheric bores exhibit large brightness amplitudes (typically 10%) and can transport large amounts of energy and momentum through the mesosphere-lower-thermosphere (MLT) region. The wave dynamics significantly affects the large-scale temperature and circulation structure of the MLT and higher atmospheric regions. Understanding the full scope of wave effects on the MLT region is important for obtaining a complete physical picture of atmospheric processes. This work will utilize the data from eight existing ground-based optical imaging systems, together with a suite of co-located multi-diagnostic instrumentation and satellite data, to investigate the global and seasonal occurrence characteristics of mesospheric bores and other frontal gravity waves in the MLT region. The effort will:1) conduct a global survey and characterization of these waves and an estimate of the momentum flux contributing to the MLT using the Boston University all-sky imager network, and2) utilize co-located ground-based multi-diagnostic measurements and satellite measurements to supplement the imager data in order to fully characterize both the propagation environment and the gravity wave propagation modes.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.