Upgrade and Operational Support for an MF Radar at Rarotonga

该提案将对位于热带南太平洋拉罗汤加（21.5S，160 W）的现有中频雷达进行现代化改造，并提供两年的业务支持。 根据这一提议，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。 雷达的工作高度范围（目前为80-98公里）将向下扩大，以跨越中间层的大部分（~60-98公里），90公里以上的测量精度将得到提高。 现有的8位数字化的动态范围已被证明是严重不足的中层MF雷达回波。 各种验证和技术研究表明，90 km以上的接收器饱和（8位操作几乎不可避免）导致风速低估。 这种偏差源将被消除，升级将使雷达更可靠，并提高其整体性能。 拉罗汤加位于目前没有测量能力的关键纬度带，与夏威夷考艾岛现有的中频雷达几乎精确共轭（同经度、反纬度）。 热层电离层中间层能量学和动力学（TIMED）卫星使命（2000年5月开始）将促进对卫星仪器和多个地面站点的数据进行综合分析。对于相关的全球性研究的现象，如昼夜潮汐，这是至关重要的，参与雷达提供无偏的风在系统之间具有相似的性能。

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.