Detecting Polar Cap Patches in Over-the-Horizon Radar Data

This project's objective is to advance the development of a polar cap patch detection algorithm for over-the horizon radars (OTHRs). This will generate new knowledge to improve understanding of space weather processes and open the possibility for real-time operations and forecasting of ionospheric irregularities, allowing their impact on radio wave propagation in the polar regions to be mitigated. We will meet this objective through the following goals. 1. Establish a set of criteria that reliably detect polar cap patches using OTHR backscatter characteristics. 2. Develop a reliable, automated polar cap patch detection algorithm for OTHR backscatter. 3. Advance the development of a near real-time OTHR patch detection algorithm. Polar cap patches are a well-documented space weather hazard at high latitudes. They are large- scale (of the order of 100s km) irregularities - enhancements in the ambient F-region ionosphere. Polar cap patches seed a broad spectrum of plasma density irregularities which can interfere with ground and spaced-based communications, detection, and navigation systems, and deviate the signal path of OTH communications and monitoring systems. Despite these advantages, there are currently no automated patch detection algorithms that use OTHR backscatter data. Our objective is to create an algorithm that will increase the ability to detect and study patches, improve scientific reproducibility by providing criteria and application methods that can be used with HF OTHRs, and improve space weather monitoring efforts at high latitudes. The expected deliverables from this proposal include an OTHR patch detection algorithm that operates reliably in a post-processing environment and a prototype of the same algorithm that is suitable for real-time operations. The proposed project will also obtain metrics and requirements from potential end users of the real-time operational patch detection algorithm that will make it possible to assess the suitability of the prototype for the Navy's space weather operational needs. This will be a valuable data input into NIMO, the Next-generation Ionospheric Model for Operations. NIMO would be able to assimilate the locations of patches, improving their high latitude data assimilation and ionospheric specification. The expected results of this proposal include a statistical study on the topic of OTHR backscatter in the polar cap region. The statistical study focuses on polar backscatter characteristics from regions with and without patches, and will provide valuable information about the variations of HF backscatter due to solar and geomagnetic conditions. This proposal is expected to produce several manuscripts suitable for submission to peer reviewed scientific journals