Continuation of Radar Studies of the Equatorial Ionosphere

这个项目涉及赤道上层大气和电离层的动力学。在秘鲁利马附近的Jicamarca射电天文台，将使用甚高频（VHF）雷达探测50公里至1000公里高度的大气区域。该设施由秘鲁地球物理研究所在国家科学基金会的支持下运营，是现有最大的大气甚高频雷达设施，也是同类设备中唯一位于赤道纬度的仪器。研究将集中在电离层等离子体的不稳定性（干扰大约100公里高度以上高层大气电离成分平衡分布的过程），以及对50至100公里区域的风、大气波和湍流的测量。利用多接收天线的干涉雷达成像技术，测量沿地磁场方向和垂直于地磁场方向的等离子体不规则形状；这样的测量将有助于建立等离子体不稳定演化的模型。时间分辨率将足以在约7度视场（100公里高度约12公里水平距离）内测量等离子体结构的漂移速度和时间演化。在50至100公里区域的测量将针对风、浪和湍流过程之间的相互作用，以及湍流强度的高度分布。适用于这种测量的各种雷达技术也将得到改进和比较。

This project is concerned with the dynamics of the equatorial upper atmosphere and the ionosphere. The 50 km to 1000 km altitude region of the atmosphere will be probed using a very high frequency (VHF) radar at the Jicamarca Radio Observatory near Lima, Peru. This facility, operated by the Geophysical Institute of Peru with support form the National Science Foundation, is the largest atmospheric VHF radar facility in existence, and the only instrument in its class located at equatorial latitudes. Studies will focus on ionospheric plasma instabilities (processes which disturb the equilibrium distribution of the ionized component of the upper atmosphere above roughly 100 km altitude), and on measurements of winds, atmospheric waves and turbulence in the 50 to 100 kilometer region. The shapes of plasma irregularities along and perpendicular to the geomagnetic field direction will be measured using interferometric radar imaging techniques which make use of multiple receiving antennas; such measurements will aid in developing models of plasma instability evolution. Time resolution will be sufficient to measure the drift velocity and temporal evolution of plasma structures in a field of view of approximately 7 degrees (about 12 km horizontal distance at 100 km altitude). Measurements in the 50 to 100 km region will be aimed at the interactions between wind, wave, and turbulence processes, and the altitude distribution of turbulence strength. Various radar techniques suitable for such measurements will also be improved and compared.