Radio Wave Scattering from Rough Surfaces -- Theory and Application to Maritime Remote Sensing with HF and other Radar Technologies

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For almost 50 years, radars of various kinds have become important in novel ocean remote sensing applications. The applicant's research team members have been leaders in investigating high frequency surface wave radars (HFSWRs) (wavelengths of 10 to 100 metres (m)), and, more recently, X-band nautical radars (of 4 to 10 centimetre wavelengths).   In addition, radars operating in the upper very high frequency (VHF) (1-m waves) to lower ultrahigh frequency (UHF) (1.6-m waves) bands have been used to study the properties of sea ice. Very recently, the team has begun to include satellite and airborne synthetic aperture radars (SAR), with typical operating wavelengths around 24, 6 and 3 centimetres (L-, C- and X-band), in their arsenal of remote sensing instrumentation for measuring sea state, weather conditions, and ground cover and wetlands properties. HFSWR resolution is much lower than that of the higher-frequency radars, but HFSWR signals can be used to detect ocean conditions and objects such as ships, ice and icebergs, and low-flying aircraft, on and near the surface, well beyond the line-of-sight horizon. Under the proposed research program enhancements to fundamental electromagnetic scattering theory and algorithms will lead to the ability to extract maritime target and environmental information (eg., wave heights, surface currents, wind velocities), from the radar signals when sea states are very high.  Better characterization of ionospheric signal contamination and improved HFSWR operation from ocean platforms will also ensue. The results will be important to oceanographers and search and rescue operators, and will enhance safety in commercial ventures such as the offshore oil and gas industry. The lower-resolution of HFSWR will be augmented by improved image processing techniques for the much-higher-resolution, howbeit line-of-site, X-band radars.  Algorithm development involving deep learning for SAR applications will also enhance the overall capacity for observation of wetlands and coastal waters. In addition to the above initiatives, investigations will continue on using VHF-UHF frequencies to determine the properties of sea ice and ice ridges, an increasingly important topic as commercial and territorial interests become focused on the Canadian Arctic. NSERC has been crucial in supporting Canada as a world leader in both theoretical and applied aspects of radar remote sensing, while leading to the export of the technology internationally. The proposed work will continue to attract scientific, commercial and maritime security interests. Perhaps most-importantly, the essential analytical, computing and critical thinking skills developed by the training of highly qualified personnel under the proposed program will be vital in bolstering Canada's capacity, not only in maritime applications, but also in many industrial settings (eg. the automotive and natural resource sectors), where such skills are becoming increasingly important.