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

该合作项目包括NWRA和汉普顿大学，支持对地球大气层区域内大气动力学的研究，该区域是近地轨道卫星或气球无法到达的。与山区地形上的气流相关的空气受到一类称为“山波”的“初级”大气重力波（GWs）的干扰。这些波浪在70公里以下的低层或中层大气中破裂或达到临界水平。这一过程不仅产生了水平波长远小于MWs的小规模次级GWs，而且还产生了水平“体力”（即在空间和时间上定位的水平加速度）。这反过来又被认为激发出比MWs水平波长更大的二次GWs的广谱。本研究的主要目的是通过这一多步骤耦合过程，尽可能量化来自毫瓦衰减的二次和三次吉瓦对热层（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结合。一名与汉普顿大学有关的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。将分析重力场和稳态海洋环流探测器（GOCE）卫星的数据，提取地球上特定区域观测到的GWs参数，并将模拟结果与这些卫星观测结果进行比较。该项目将涉及将这些结果应用于MWs的研究，以调查影响热层的二次和三次波的产生程度。如果这项研究成功，将极大地促进研究界对这种多步耦合过程中由地形强迫通过GWs向热层的动量转移过程的理解。这项研究预计将从这些过程（即从下面的空间天气）中更好地了解热层的变化和结构，从而有助于实现重大的更广泛的影响，因为如果该奖项所代表的研究工作能够更全面地理解这种动量转移过程，就可能开发出对这种热层波结构的预测能力。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 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.