Upgrade and Operational Support for an MF Radar at Rarotonga

这项提议将用于热带南太平洋拉罗通加(21.5s，160W)的现有中频雷达的现代化，并提供为期两年的业务支助。根据这项提议，将安装一个新的数据采集系统，并将8位接收器升级为12位或16位数字化。雷达的作用高度范围(目前为80-98公里)将向下扩展到覆盖大部分中间层(~60-98公里)，测量精度将提高到90公里以上。现有的8位数字化的动态范围已被证明严重不足以满足中层微波雷达的返回。各种验证和技术研究表明，接收器饱和超过90公里(这在8位操作中几乎是不可避免的)会导致风级被低估。这一偏差来源将被消除，升级将使雷达更加可靠，并提高其整体性能。拉罗通加位于一个关键的纬度带，目前没有测量能力，几乎与夏威夷考艾岛现有的MF雷达共轭(相同经度，相反纬度)。热层电离层、中间层能量和动力学(TIMED)卫星飞行任务(2000年5月开始)将促进来自卫星仪器和多个地面站点的综合数据分析。对于像全日潮汐这样的现象的相关全球研究来说，参与的雷达必须在整个系统中提供具有类似表现的无偏风。

This proposal would provide for the modernization of an existing MF radar at Rarotonga (21.5S, 160W) in the tropical southern Pacific and operational support for two years. Under this proposal, a new data acquisition system would be installed and the 8-bit receivers upgraded to 12- or 16-bit digitization. The operational height range of the radar (currently 80-98 km) will be expanded downward to span most of the mesosphere (~60-98 km), and the measurement accuracy above 90 km will be improved. The dynamic range of the existing 8-bit digitization has been shown to be grossly inadequate for mesospheric MF radar returns. A variety of validation and technical studies have demonstrated that receiver saturation above 90 km (which is nearly unavoidable with 8-bit operation) results in wind magnitude under-estimates. This source of bias will be eliminated and the upgrade will make the radar more reliable and increase its overall performance. Rarotonga is situated in a key latitude belt where there are presently no measurement capabilities and is almost precisely conjugate (same longitude and opposite latitude) to an existing MF radar at Kauai, Hawaii. The Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite mission (beginning in May 2000) will foster combined data analysis from satellite instruments and multiple ground-based sites. For correlative global studies of phenomena like the diurnal tide it is essential that the participating radars provide unbiased winds with similar performance across systems.