CEDAR: Effects of Orographic Forcing on the Southern Mid-Latitude Mesosphere

这次调查将确定地形强迫的特征及其对中间层重力波总发生的贡献。该项目需要估计与山波有关的动量和能量通量以及通量散度的水平，即进入中间层顶区域的波沉积。该项目的目标将通过对中间层-低层热层（MLT）山波的全天成像观测来实现，并结合位于阿根廷El Leoncito天文台的几种类型的多诊断仪器进行测量，提供羟基和氧风、温度和亮度。另外还将利用卫星测量的MLT温度和气辉发射率，以及对流层/平流层风和温度，以便获得波的起源和行为的全面特征。该项目的主要目的是分析由西风穿过安第斯山脉产生的重力波数据，并通过其对羟基，氧气和钠气辉排放的影响在直接下风区域成像。山波事件将利用从卫星辐射获得的对流层和平流层温度测量来确定。这些测量，结合对流层和平流层的平均风信息，将描述山波产生的强迫条件。其他卫星测量将提供覆盖大气很大垂直范围的平均状态温度，这将有助于将低层大气测量与MLT区域测量联系起来。大气重力波的地形强迫问题是确定各种对流层过程与高层大气耦合的重要性的努力的一部分，目前引起人们的兴趣。这项工作将推动这些努力。

The investigation will determine the characteristics of orographic forcing and its contribution to the total occurrence of mesospheric gravity waves. The project entails the estimation of the momentum and energy flux associated with the mountain waves as well as the level of flux divergence, i.e., wave deposition, into the mesopause region. The project goals will be achieved using all-sky imaging observations of the mesosphere-lower thermosphere (MLT) mountain waves in conjunction with measurements from several types of multi-diagnostic instrumentation co-located at the El Leoncito Observatory in Argentina providing hydroxyl and oxygen winds, temperatures, and brightness. Additional satellite measurements of MLT temperature and airglow emission rate, as well as tropospheric/stratospheric winds and temperatures, will also be utilized in order to obtain a comprehensive characterization of the origin and behavior of the waves.The primary thrust of the project is to analyze gravity wave data generated by westerly winds flowing across the Andes and imaged in the immediate downwind region by their effects on the hydroxyl, oxygen, and sodium airglow emissions. Mountain wave events will be identified using tropospheric and stratospheric temperature measurements obtained from satellite radiances. These measurements, combined with mean wind information in the troposphere and stratosphere, will characterize the forcing conditions for mountain wave generation. Other satellite measurements will provide mean state temperature covering a large vertical extent of the atmosphere which will help tie the lower atmosphere measurements to the MLT region measurements. The subject of orographic forcing of atmospheric gravity waves is of current interest as part of efforts to determine the importance of coupling of various kinds of tropospheric processes to the upper atmosphere. The work will advance these efforts.