Strategies for Operating HF Radars in Field of View of Offshore Wind Turbines

Oceanographic High Frequency (HF) radars are used to monitor coastal ocean conditions, such as waves and surface current velocities, up to 250 km from shore in near real-time. Applications using HF radar outputs include search and rescue, oil spill response, harmful algal bloom monitoring, tsunami detection, among others. Offshore wind turbines in the field of view of HF radars act as strong reflectors and can cause interference, leading to loss and/or bias in the oceanographic measurements. With the current U.S. administration's goal of deploying 30 gigawatts (GW) of offshore wind by 2030, offshore wind farms in the United States are expected to drastically increase in the coming years from the seven turbines currently operating in U.S. waters. This paper summarizes current understanding of wind turbine interference (WTI) on HF radar data as well as current best practice recommendations for mitigating the effects of WTI on HF radar networks. Present mitigation methods fall into three categories including, altering how radars are configured or run, using software to flag data containing WTI, and altering the design of the radar network to increase redundancy.