CEDAR: Downward Progression of Temperature Anomalies during Sudden Stratospheric Warmings

极地大气经常表现出意想不到的、显著的温度异常，称为平流层突然变暖（SSWs），它呈下降趋势。异常的发展可以从接近80公里高度的中间层和低层热层区域开始，一直到30公里左右的对流层高度。由于其向下的过程，ssw代表了大气区域之间向下耦合的一个重要过程。它们被认为是行星波和平均大气流（风）相互作用的产物，但也有人提出，来自较低高度的大气扰动（重力波）在这种相互作用中起着重要作用，因为它为向下发展创造了适当的条件（预调节）。研究工作将利用最近获得的资料同化运行结果，并结合若干大气模式。高层和中层大气的向下耦合过程很重要，因为它们对平流层臭氧和其他重要成分有潜在的影响。研究工作将包括：(1)利用卫星测量数据和全球大气模式结果分析温度异常和大气波的特征；(2)数值模拟波的传播，并将结果与温度异常特征进行比较；(3)运行集合模拟，通过零风线高度的变化来研究是否发生了预调节。这项工作将提高对大气波在极地高层大气中向下耦合中所起作用的理解，并可能提高模拟气候和空间天气干扰的能力。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。

The polar atmosphere often exhibits unexpected and significant temperature anomalies called Sudden Stratospheric Warmings (SSWs) that show a downward progression. The progression of anomalies can start in the mesosphere and lower thermosphere region near 80 km in altitude and go all the way down to tropospheric heights of around 30 km. Because of their downward progression, SSWs represent an important process for downward coupling between atmospheric regions. They are believed to be a product of interaction between planetary waves and the mean atmospheric flow (winds), but it has also been suggested that atmospheric disturbances originating from lower altitudes (gravity waves) play an important role in this interaction by creating the right set of conditions for downward progression (pre-conditioning). The research work will exploit the recently obtained results of data assimilation runs in combination with a number of atmospheric models. The downward coupling processes in the upper and middle atmosphere are important because of their potential impact on the stratospheric ozone and other important constituents. The work will involve (1) analysis of characteristics of the temperature anomalies and atmospheric waves using data from satellite measurements and global atmospheric model results, (2) numerical simulations of wave propagation and comparison of the results with characteristics of the temperature anomalies, and (3) investigation of whether pre-conditioning occurs through a change in the zero-wind line height by running ensemble simulations. This work will improve the understanding of the role that atmospheric waves play in downward coupling in the polar upper atmosphere and can potentially improve the ability to model climate and space weather disturbances.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.