CEDAR: Quantifying Mesospheric Gravity Waves and Associated Temperature Variability Over the Andes

这个项目是一项新的实验研究，旨在量化重力波在南美洲，特别是安第斯山脉附近的中间层和低热层(MLT)区域(约80-100公里)的动力学、动量输送、沉积和随后的强迫中所起的作用。安第斯地区是研究重力波对MLT动力学影响的极好的天然实验室。在夏季的几个月里，主要的重力波强迫是由大陆以东的强雷暴引起的深层对流造成的。在冬季，由于从太平洋向东吹来的强烈纬向风突然遇到了高耸的安第斯山脉，强烈的地形强迫占主导地位。这就产生了大幅度波，这些波已经被测量到平流层很好，但在MLT高度还没有明确测量到。有很强的理论理由认为它们会很好地渗透到中间层，特别是在冬季。在毛伊岛-麦芽项目(2002年至2006年)取得巨大成功的基础上，该项目将在智利塞罗托洛市部署和远程操作犹他州立大学雪松中层温度测绘仪(S 30.1W，功率70.8W)。MTM是一种坚固耐用的高性能CCD成像系统，旨在通过对两个重要的气辉发射进行精确观测来提供关于重力波的关键温度和强度测量，这两个发射是位于87公里附近的近红外OH(6，2)和接近94公里的O2(0，1)大气波段。这些数据提供了一种独特的能力来量化在MLT高度的波的传播、增长和消散。计划与风温激光雷达、流星雷达、全天成像仪和其他光学仪器协调执行这些新的测量，作为在毛伊岛-马尔特计划期间成功采用的经过充分证明的仪表组的一部分。主要目标是：1)利用协调的波、风和温度测量，量化安第斯山脉上广泛的波(包括重力波、潮汐和行星波)的影响和季节变化；2)对冬季MLT高地存在的山波进行独特的调查，量化其特征和相关的动量通量，并与夏季由于对流强迫而进行的类似测量进行比较。该项目的更广泛影响包括学生的大力参与，这将有助于培训下一代研究人员新颖的光学测量和图像处理技术。此外，重力波在推动MLT的平均和可变结构方面的公认作用使理解它们的各种贡献成为大气学社区的高度优先事项。特别是，需要能够在最先进的模型中准确地描述这些影响，这对于预测它们在变化的太阳强迫和气候变化条件下的区域、季节和全球影响具有广泛的意义。

This project is a novel experimental investigation to quantify the role of gravity waves on the dynamics, momentum transport, deposition and subsequent forcing of the Mesosphere and Lower Thermosphere (MLT) region (~80-100 km) over South America, and specifically near the Andes Mountains. The Andes region is an excellent natural laboratory for investigating gravity wave influences on the MLT dynamics. During the summer months the dominant gravity wave forcing results from deep convection arising from severe thunderstorms over the continent to the east. During the winter, strong orographic forcing dominates, due to intense prevailing zonal winds blowing eastward from the Pacific Ocean which suddenly encounter the towering Andes mountain range. This creates large amplitude waves that have been measured well into the stratosphere but have yet to be unambiguously measured at MLT heights. There are strong theoretical reasons to expect them to penetrate well into the mesosphere, especially during the winter months. Building on extensive experience gained as part of the highly successful Maui-MALT program (2002-2006), this project will deploy and remotely operate the Utah State University CEDAR Mesospheric Temperature Mapper (MTM) at Cerro Tololo, Chile (30.1 S, 70.8 W). The MTM is a robust, high-performance CCD imaging system designed to provide key temperature and intensity measurements on gravity waves using precise observations of two prominent airglow emissions, the NIR OH(6,2) centered near 87 km, and the O2(0,1)Atmospheric band, near 94 km. These data afford a unique capability to quantify wave propagation, growth, and dissipation at MLT heights. It is planned to perform these new measurements in coordination with Na wind-temperature lidar, meteor radar, all-sky imager and other optical instruments as part of a well proven instrument cluster, as employed successfully during the Maui-MALT program. The primary goals are: 1) To quantify the impact and seasonal variability of a broad spectrum of waves (including gravity waves, tides and planetary waves) over the Andes using coordinated wave, wind, and temperature measurements; 2) To perform a unique investigation of mountain waves present at MLT heights during winter months, quantifying their characteristics and associated momentum fluxes, and comparing with similar measurements during the summertime due to convective forcing. The broader impact of the project includes strong student involvement, which will contribute to training the next generation of researchers in novel optical measurements and image processing techniques. In addition, the recognized role of gravity waves in driving the mean and variable structure of the MLT makes an understanding of their various contributions a high priority for the aeronomy community. In particular, the need to be able to accurately describe these effects in state-of-the-art models has broad implications for predicting their regional, seasonal and global influences under variable solar forcing and climate change conditions.