Oblique Sounding of Ionized Patches in the Antarctic Ionosphere - Instrument Development and Testing

已知与电离斑块相关的电离层结构会干扰高纬度地区的无线电信号，对搜救行动和其他无线电通信产生重要影响。这些问题在人口稀少、没有有线通信网络的地区具有高度相关性。最近的统计研究表明，在~300公里高度离子化斑块有很强的年发生趋势。斑块出现的高峰似乎出现在同一个月的北（北极）和南（南极）极地。这与预测季节性趋势的既定理论相反，在每个半球的冬季月份，斑块的发生达到高峰。虽然观测到的年度趋势与北极的预测和了解相吻合，但在南极的趋势与预期完全相反。目前迫切需要利用独立的探空观测，以及现有电离层雷达（如SuperDARN）对电离层电场行为的观测，来确认南极斑块的发生率。这两种类型的观测都需要确定产生这些电离斑块的物理机制。在南极站部署的现有地球空间仪器不能满足这些目标。该合同将支持低功率自主电离层探测仪的开发，该探测仪将允许在南极的两个美国载人站之间对南极电离层进行倾斜探测测量。电离层探空仪的发射机将安装在麦克默多，并向南极发射无线电脉冲，在那里，电离层探空仪的接收器将从这种电离斑的倾斜探测中收集数据，跟踪它们的形成、传播和动态。在南极洲对这台仪器进行长达12个月的测试，也将使科学家能够收集到足够的实验数据，从而有可能在南极偏远地区部署一组电离层探空仪发射器。各种探测信号将在南极电离层探空仪的集线器接收器上接收和处理。

Ionospheric structures associated with ionized patches are known to disrupt radio signals at high latitudes, with important consequences for search-and-rescue operations and other radio communications. These issues are highly relevant in sparsely populated regions, where wired communications networks are unavailable. Recent statistical studies have shown a strong annual occurrence trend of ionized patches at ~300-km altitude. Patch occurrences appear to peak in the same months across both the Northern (Arctic) and Southern (Antarctic) polar regions. This is in contrast with established theories that predict a seasonal trend, with patch occurrence peaking in winter months in each hemisphere. While the observed annual trend matches what is predicted and understood in the Arctic, the trend runs completely opposite to what is expected in the Antarctic. There is an urgent need to confirm the Antarctic patch occurrence rates using independent sounding observations, along with observations of the ionospheric electric field behavior from existing ionospheric radars such as SuperDARN. Both types of observations are needed to determine the physical mechanisms that produce these ionized patches. The existing geospace instrumentation deployed at Antarctic stations is not capable of meeting these objectives. This award will support the development of a low-powered, autonomous ionosonde that would allow oblique sounding measurements of the Antarctic ionosphere between two manned U.S. stations in the Antarctic. The ionosonde's transmitter will be installed at McMurdo and send radio pulses towards South Pole, where the ionosonde's receiver will collect data from this oblique sounding of ionized patches, following their formation, propagation, and dynamics. The 12-months long period of testing this instrument in Antarctica will also allow scientists to collect enough experimental data to potentially deploy an array of ionosonde transmitters at remote Antarctic locations. The various sounding signals will be received and processed at the ionosonde's hub receiver at South Pole.