CEDAR: ALOHA/ANLC-93; Airglow Imaging Studies

这项提议涉及使用NCAR Electra飞机的宽视场成像仪研究大气气辉和夜光云(ANLC)，用于ALOHA/ANLC-93战役。该成像器将为这一行动提供相关数据，包括激光雷达、雷达和来自上中间层-下热层区域的光谱信息。活动的基本目标是定位和研究与ANLC、重力波动力学和零星的Na层有关的地球物理条件。除了为这些团队目标提供观测贡献外，还将对从这些数据解析的重力波的水平属性进行具体研究，并将其与1991-92年在德克萨斯州熊湖用这里建议的相同仪器在7个月期间获取的现有数据集进行比较。洛克希德公司已经开发并在几次地面战役中成功展示了一种灵敏的、裸露的CCD成像仪，能够测量高信噪比的OH、O2、Na和OI夜光。特别是，使用宽带技术(7500-9300和gt；)的OH成像已经产生了50：1的S：N，60张S曝光，使用全天空光学系统的0.35o像素(头顶上的分辨率为0.5公里)。在这种灵敏度下，已经观察到气辉强度幅度在几个百分点的数量级。该阵列是一个1024×1024(15.4 mm×15.4 mm)的阵列，比目前用于气动研究的商用阵列大4倍。该系统使用商用电子设备(包括一台计算机)，这些设备坚固耐用，性能稳定，适用于飞机环境。已经与NCAR进行了协调，在飞机上安装了一个全天穹顶，以容纳全天场。飞机的俯仰和滚转稳定性研究表明，在典型的飞行条件下，30秒内的角度分辨率可以达到&gt；5度。宽视场相机将被用来记录(1)由大气重力波和潮汐影响飞行段中太阳仰角(海)-10度(这是行动中大多数飞行路线的条件)的OH气辉层中的不规则性；(2)拍摄夜间光云的太阳散射照明图像，其中ANLC阶段为-60度；(3)对海面上的钠闪电进行成像，为零星的钠层研究提供支持。观察结果(2)和(3)在计划的两次向北进入极冠的飞行中是可行的。在目标(1)中，将利用OH图像来研究水平波长、强度幅度、视水平相速度和空间范围(最大半径为500公里的飞机)。对图像进行谱密度分析，解析水平重力波信息。在ANLC活动中，将尝试对云进行m次观测，以提供ANLC位置的信息。从闪光灯拍摄的图像中，钠的密度将从图像中反转。对于非常特定的位置(即，SEA&GT；-6.5°)，钠柱密度将从假设的层的恒定太阳照度的图像中得出。

This proposal involves the study of atmospheric airglow and noctilucent clouds (ANLCs) with a wide field imager from the NCAR Electra aircraft for the ALOHA/ANLC-93 campaign. The imager will provide correlative data to the campaign which includes lidar, radar, and spectroscopic information from the Upper Mesosphere- Lower Thermosphere region. The basic campaign objectives are to locate and study the geophysical conditions associated with ANLCs, gravity wave dynamics, and sporadic Na layers. In addition to providing an observational contribution to these team goals, a specific study of the horizontal attributes of gravity waves resolved from these data will be performed and compared to an existing data set which was taken over a 7 month period in 1991-92 at Bear Lake, UT with the same instrument that is proposed here. Lockheed has developed and successfully demonstrated in several ground based campaigns, a sensitive, bare CCD imager capable of measuring OH, O2, Na, and OI nightglows with high signal to noise ratios. In particular, OH imaging using broad band techniques (7500-9300 >), have produced 50:1 S:N with 60 s exposures using .35o pixels (>.5 km resolution overhead) with all- sky optics. With this sensitivity, airglow intensity amplitudes on the order of a few percent have been observed. The array is a 1024 X 1024 (15.4mm X 15.4mm) which is >4x larger than the commercially available arrays used in aeronomical studies to date. The system uses commercial electronics (including a computer) which are rugged and stable for the aircraft environment. Coordination has been made with NCAR to install an all-sky dome on the aircraft to accommodate the all-sky field. Aircraft pitch and roll stability have been investigated to suggest that, for typical flight conditions, angular resolutions of >.5o over 30 seconds can be achieved. The wide field camera will be used to (1) document irregularities in the OH airglow layer which are caused by atmospheric gravity waves and tides affecting the layer for flight segments where the Solar Elevation Angle (SEA)-10o (which is the condition for most flight paths for the campaign); (2) image solar scattered illumination of noctilucent clouds where -6oSEA-8o for the ANLC phase; and (3) image the Na 'sodium flash' at SEA>-6.5o in support of the study of sporadic Na layers. Observations (2) and (3) are feasible on the two planned flights north into the polar cap. With the OH imagery, the horizontal wavelength, intensity amplitude, apparent horizontal phase velocity, and spatial extent (up to 500 km radius of the aircraft), will be studied in objective (1). Spectral density analysis will be performed on imagery to resolve the horizontal gravity wave information. In the ANLC campaign,m observations of the clouds will be attempted to provide information of ANLC's location. From Na 'flash' imagery, the Na density will be inverted from the image. For a very specific location (i.e. SEA>-6.5o) the Na column density will be derived from the image for an assumed constant solar illumination of the layer.