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

NWRA和汉普顿大学共同参与的这一合作项目支持对低地球轨道卫星或气球无法进入的地球大气层区域内大气动力学的研究。与山区上空的风流有关的空气会受到一种被称为“山波”(MWs)的“初级”大气重力波(GWS)的干扰。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。这一过程不仅产生了水平波长比MW小得多的小尺度次级GW，而且还产生了水平“体力”(即在空间和时间上的水平加速度)。它们反过来又被认为激发了水平波长比MW更大的广泛光谱的次级GW。这项研究的主要目的是通过这种多步骤耦合过程，尽可能地量化微波衰减产生的第二和第三GWS对热层(200公里以上的中性大气)的影响。这项研究包括详细的、有针对性的建模和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所述的研究工作。将依次使用几种不同的模拟来模拟整个过程。来自重力场和稳态海洋环流探测器(GOCE)卫星的数据将被分析，以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对微波的研究，以调查影响热层的第二波和第三波的产生程度。这项研究如果成功，将大大促进研究界对在这一多步骤耦合过程中通过GWS从地形强迫到热层的动量转移过程的理解。这项研究有望更好地了解热层在这些过程中的变异性和结构(例如，从下面的空间天气)，从而帮助实现重大的更广泛的影响，因为如果作为该奖项所代表的研究工作的结果，对这种热层波结构的预测能力可能被开发得更全面。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为是值得支持的。

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.