Collaborative Research: Modeling of Secondary and Tertiary Gravity Waves from Orographic Gravity Wave Forcing and Comparison with Satellite Observations

这一涉及西北无线电协会和汉普顿大学的合作项目支持对地球大气层区域内的大气动力学进行研究，因为低地球轨道卫星或气球无法进入该区域。与山区地形上的风流动相关的空气被称为“山脉波”（MW）的“初级”大气重力波（GW）扰动。这些波在70公里以下的低层或中层大气中破裂或达到临界水平。该过程不仅产生水平波长远小于MW的小规模次级GW，而且还产生水平“体积力”（即，在空间和时间上局部化的水平加速度）。这些反过来被认为激发了一个广泛的光谱的二级GW的水平波长大于MW。研究的主要目的是尽可能量化MW衰减产生的二次和三次全球Ws通过这一多步耦合过程对热层（200公里以上的中性大气）的影响。该研究包括详细的、有针对性的建模与数据分析研究的独特组合。汉普顿大学的一名研究生将参与上述研究工作。将依次使用几种不同的模拟来模拟整个过程。将对重力场和稳态海洋环流探测器（GOCE）卫星的数据进行分析，以提取地球上特定区域观测到的全球变暖参数，并将模拟结果与这些卫星观测结果进行比较。该项目将把这些结果应用于微波研究，以调查产生影响热层的二次波和三次波的程度。研究如果成功，应大大推进研究界的认识的过程中的动量转移从地形强迫热层通过全球变暖，在这个多步骤的耦合过程。这项研究预计将导致从这些过程中更好地了解热层的可变性和结构（即，从下面看太空天气）因此，有助于实现一个显著的更广泛的影响，因为预测这种热层波结构的能力可能会得到发展，如果这种动量传递过程作为这个奖项所代表的研究工作的结果得到更全面的理解的话。这个奖项反映了美国国家科学基金会的法定使命，并且通过利用基金会的智力价值和更广泛的影响进行评估，被认为是值得支持的审查标准。

This collaborative project involving both NWRA and Hampton University supports a study of atmospheric dynamics within the region of the Earth's atmosphere that is not accessible by low Earth orbiting satellites or by balloons. Air that is associated with the wind flow over mountainous terrain is disturbed by a class of 'primary' atmospheric gravity waves (GWs) that is called 'mountains waves' (MWs). These waves break or reach critical levels in the lower or middle atmosphere at altitudes below 70 km. This process not only creates small-scale secondary GWs with horizontal wavelengths considerably less than that of the MWs, but also creates horizontal 'body forces' (i.e., horizontal accelerations localized in space and time). These in turn are thought to excite a broad spectrum of secondary GWs with horizontal wavelengths larger than that of the MWs. The main objective of the research is to quantify to the extent possible the effect that secondary and tertiary GWs from MW attenuation has on the thermosphere (the neutral atmosphere above 200 km) via this multi-step coupling process. The research includes a unique combination of detailed, targeted modeling combined with data analyses studies. A graduate student associated with Hampton University would participate in the research work described.Several different simulations would be used in sequence to simulate the entire process. Data from the Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite would be analyzed to extract GWs parameters observed for specific regions on Earth, and the simulations will be compared to these satellite observations. The project will involve applying these results to the study of MWs to investigate the extent to which secondary and tertiary waves that affect the thermosphere are produced. The research if successful should significantly advance the research community's understanding of the process of momentum transfer from orographic forcing to the thermosphere via GWs in this multi-step coupling process. This research is expected to lead to a much better appreciation of the variability and structure of the thermosphere from these processes (i.e., space weather from below) thus helping to achieve a significant broader impact because a predictive capability might possibly be developed for such thermospheric wave structures were this momentum transfer process be understood much more completely as a result of research work represented by this award.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.