F-region ionization patches in High Frequency over-the-horizon radar data

Ionization patches are a common feature of the polar-cap, F-region ionosphere. Patches can be detected using a variety of remote sensing instruments including optical imagers and incoherent scatter radars. Due to their pronounced plasma density gradients, patches are believed to be a strong source of decameter-scale field-aligned-irregularities which are responsible for ionospheric backscatter observed by High Frequency (HF; 3 – 30 MHz) over-the-horizon (OTH) radar systems. Indeed, Super Dual Auroral Radar Network (SuperDARN) systems at high latitudes have been used for investigating polar-cap patches for decades. Current techniques for identifying patches in SuperDARN ionospheric backscatter data are rudimentary and labor intensive as they require human intervention—an automated detection algorithm does not yet exist. This presentation will detail progress on the development of an automated algorithm for detecting patches in SuperDARN ionospheric backscatter data. The end-goal of the development effort is to transition the algorithm into a near real-time patch detection capability for SuperDARN and other OTHR systems. Patches are an important signature of magnetosphere-ionosphere-thermosphere (M-I-T) coupling in the polar regions; they are also an agent of space weather as they are a source of HF scintillation there. An automated algorithm for detecting patches will allow for their potentially hazardous influence on HF radio wave propagation conditions to be identified and mitigated.