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

Johns Hopkins University, Baltimore MD

Investigators

Abstract

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.