CEDAR: Climatology and Characteristics of Instabilities and Atmospheric Gravity Waves at Low and Mid Latitudes

利用三个测点的光学和近红外成像资料研究了中低纬度重力波的来源和特征。分析了夏威夷Maui MALT(中层和低热层)大气观测站、澳大利亚阿德莱德和澳大利亚爱丽斯斯普林斯的现有数据，并收集了新的数据。毛伊岛麦芽的成像仪在1600 nm附近对非常明亮的OH Meinel辐射进行采样，因此能够非常快速地采样，在一秒钟内实现100的信噪比。该成像仪是唯一能够捕捉快速移动的短周期重力波结构的成像仪，将用于研究在Brunt-Vaisala周期(名义上为5分钟)附近的重力波周期中出现峰值的可能性，以及在该周期较短的重力波周期中出现急剧频率截止的相应可能性。毛伊岛麦芽成像仪的数据也被用来描述OH气辉层中小尺度不稳定特征的性质。确定了这些特征与对流不稳定层的关系以及这些不稳定层的厚度，并对这些不稳定层的形态和气候学进行了表征。澳大利亚的仪器是传统的光学成像仪，相隔1500公里。来自这些地点的数据被用来研究可能的对流层对流源，中心位于达尔文爱丽丝斯普林斯以北约1300公里处。由于爱丽丝斯普林斯和阿德莱德之间没有地形特征，澳大利亚的成像仪提供了一个很好的机会来分离麦芽重力波的对流层来源的作用。

Optical and near infrared imaging data from three sites are used to investigate the source and characteristics of gravity waves at low and mid-latitudes. Extant data from sites at the Maui MALT (Mesosphere and Lower Thermosphere) Atmospheric Observatory in Hawaii, at Adelaide Australia, and at Alice Springs Australia are analyzed, and new data are gathered. The imager at Maui Malt samples extremely bright OH Meinel emissions near 1600 nm, and is therefore capable of very fast sampling, achieving a signal-to-noise ration of 100 in one second. This imager is uniquely capable of capturing fast moving, short period gravity wave structures, and will be used to examine the possibility of a peak in gravity wave periods near the Brunt-Vaisala period (nominally five minutes), and the corresponding possibility of a sharp frequency cutoff for gravity wave periods shortward of this period. The Maui MALT imager data are also used to characterize the nature of small-scale instability features in the OH airglow layer. The relationship of these features to convectively unstable layers as well as the thickness of these layers is determined, and the morphology and climatology of these instabilities is characterized. The instruments in Australia are conventional optical imagers, separated by 1500 km. Data from these sites are used to examine a possible tropospheric convective source centered approximately 1300 km north of Alice Springs in Darwin. Due to the absence of orographic features between Alice Springs and Adelaide, the Australian imagers offer an excellent opportunity to isolate the role of tropospheric sources of MALT gravity waves.