Collaborative Research: Instabilities and Turbulence in Gravity Wave Dissipation and Formation of Thermospheric Sodium Layers above the Andes

该奖项将资助智利Cerro Pachon（30.25 S，70.74 W，elev.）的安第斯山脉激光雷达天文台（ALO）的钠（Na）风温（W T）激光雷达的持续运行。2530米），支持科学研究的目的是中层顶大气不稳定性和湍流结构的形成动力学的重力波（GW）耗散过程的空间区域以上的安第斯山脉，人口的山区GW事件是丰富的。ALO的Na激光雷达是最先进的共振荧光多普勒激光雷达，能够在80-105公里高度范围（称为MLT区域）内以出色的垂直和时间分辨率高精度测量三维风、中性温度和Na密度剖面。其他可能的W-T激光雷达研究将包括将激光雷达观测扩展到较低的热层，对热层钠层频繁出现的140公里高空进行风和温度测量。这种层的形成是不理解的，将是本奖项的一个重要研究课题。ALO天文台的另一个有趣的应用是探测与大气不稳定层的形成和GW事件的消散有关的中间层和低热层温度和风廓线中的湍流尺度扰动。这种机制适用于这些环境。这种机制的细节，在低海拔地区的气象系统相关的转换成热源，这是显着的MLT高度了解甚少。已知该转换过程与中性密度的指数下降有关。随着GW结构传播到上部区域，转换过程通过耗散过程发挥作用，该奖项将通过对观测结果与以湍流结构的启动、发展和演变问题为中心的建模研究的预测进行比较来定义。与该奖项研究领域相关的另一个问题是有机会研究将于2019年在智利发生的日全食的大气影响。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 will fund continued operations of a sodium (Na) wind-temperature (W&T) lidar at the Andes Lidar Observatory (ALO) in Cerro Pachon, Chile (30.25 S, 70.74 W, elev. 2530 m) supporting scientific studies aimed at the dynamics of mesopause atmospheric instabilities and turbulence structures formation resulting from the gravity wave (GW) dissipation processes for a spatial region above the Andes where the population of mountain GW events is abundant. The Na lidar at ALO is a state-of-the-art resonance-fluorescence Doppler lidar, capable of measuring 3D wind, neutral temperature and Na density profiles with excellent vertical and temporal resolutions within the 80-105 km altitude range (referred to as the MLT region) and with high accuracy. Other possible W&T lidar studies would include the extension of lidar observations into the lower thermosphere, with wind and temperature measurements up to 140 km altitude for the somewhat frequent occurrence of thermospheric sodium layers. The formation of such layers is not understood and will be a significant topic of research in this award. Another interesting application of the ALO observatory is the detection of turbulence scale perturbations in the mesosphere and lower thermosphere temperature and wind profiles that are related to the formation of atmospheric unstable layers and dissipation of GW events.A point of great interest was how the results of this research might be applicable to other planetary atmospheres where the same issues of fluid dynamics come into play because the same energy transfer mechanism applies to these environments. The details of this mechanism that transfers translational energy associated with meteorological systems at low altitudes into a heat source that is significant at MLT altitudes are poorly understood. This conversion process is known to be related to the decreasing exponential neutral density. As the GW structure propagates into the upper region, a conversion process comes into play through dissipation processes that this award would define by undertaking the comparison of observations with the predictions of modelling studies centered upon the question of the initiation, development, and evolution of turbulent structures. Another issue relating to this award area of study is the opportunity to study the atmospheric effects of a total solar eclipse that will be happening in 2019 in Chile.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.