AGS-PRF: Establishing Causality in the Angular Momentum Budget of the Atmosphere: Insights from the Quasi-Biennial Oscillation

该奖项全部或部分由2021年美国救援计划法案（公法117-2）资助。准两年振荡（QBO）描述了大约每27个月在中低平流层纵向平均赤道风的交替方向。随着时间的推移，这种交替模式下降到对流层顶，然后在13-19公里的高度范围内逐渐减弱。在此范围内，准两年振荡可以影响对流层急流和热带对流，从而影响全球天气和气候。QBO风的减弱可以归因于向上传播到对流层顶区域的大气波的耗散所产生的大气扭矩。到目前为止，对QBO的大气扭矩的影响，并最终对对流层环流还没有很好的理解。目前的气候模式不能很好地模拟QBO东风在对流层顶的下降，这可能是由于模式中的扭矩表示不当。这项工作旨在提高我们对大气扭矩和QBO全球影响的认识。在一个成熟的申办者的指导下，研究者将使用不同复杂性的观察结果和数值模型来实现这一目标。研究任务将侧重于测试观测和模式中的扭矩QBO关系理论，评估QBO对中纬度急流的影响，并量化扭矩对热带对流的影响。这些努力可以通过改善气候预测和区域降水和中纬度急流动力学的亚季节到季节预测来帮助提高未来的建模能力。该奖项反映了NSF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 funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).The Quasi-Biennial Oscillation (QBO) describes the alternating direction of the longitudinally averaged equatorial wind in the middle-to-lower stratosphere at roughly every 27 months. Over time, this alternating pattern descends toward the tropopause before diminishing at the altitude range of 13-19 km. In this range, the QBO can influence the tropospheric jet stream and tropical convection, thereby affecting the global weather and climate. The diminished QBO wind can be attributed to the atmospheric torque associated with the dissipation of atmospheric waves propagating upward into the tropopause region. To date, the impact of the atmospheric torque on the QBO and, eventually, on the tropospheric circulation is not well understood. Current climate models cannot properly simulate the observed descent of the QBO eastward wind across the tropopause, and this failure may be due to the improper torque representation in models.This work aims to advance our understanding of atmospheric torque and the global influence of the QBO. Mentored by a well-established sponsor, the investigator will use observations and numerical models of varying complexity to address this goal. The research tasks will focus on testing theories on the torque-QBO relationship in observations and models, assessing the influence of the QBO on the mid-latitude jet, and quantifying the influence of torques on tropical convection. These efforts could help advance future modeling capabilities by improving climate projections and subseasonal-to-seasonal forecasts of regional precipitation and mid-latitude jet dynamics. The investigator will also make public-engagement presentations to provide insight into climate change related to the research work.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.