Expansion of High-Frequency Radar Coastal Wave Observations and Applications to the National Weather Service

A pilot project is underway through a collaboration between the U.S. Integrated Ocean Observing System (IOOS) Office in the National Ocean Service (NOS) of the National Oceanic and Atmospheric Administration (NOAA) and NOAA’s National Weather Service (NWS). The pilot project will expand the capabilities of the IOOS oceanographic high-frequency radar (HFR) national network to measure wave height, period, and direction in addition to ocean surface current velocities. The initial implementation is being conducted with IOOS Regional Association (RA) partners in Central and Northern California (CeNCOOS), the Mid-Atlantic (MARACOOS), and Caribbean (CariCOOS) in coordination with HFR manufacturer CODAR Ocean Sensors, Ltd. to prepare for enabling this capability nationwide throughout all IOOS RAs. The new bimodal wave processing has the capability to separate the wind wave spectrum (distinguishable in Doppler frequency) from a swell wave component. Results showing the accuracy of HFR measurements from bimodal wave parameters detected on both the U.S. East and the West coast (station #SPRK at Seaside Park, New Jersey and #BML1 at Bodega Bay, California) are reported in Lipa (2022). These bimodal wave outputs (in addition to the traditional wave outputs currently provided) are being evaluated by the NWS for use by Weather Forecast Offices (WFO), for model development and validation, and potentially for assimilation into wave models. For example, the incorporation of bimodal wave outputs offers a paradigm shift in bias correction techniques. By dissecting wave data into sea and swell components, forecasters can pinpoint specific sources of bias and apply targeted adjustments. The HFR data supplement existing buoys and in some cases provides primary validation as well as coverage in areas without buoys. Adopting HFR ocean wave data both in nowcasting and forecasting falls within the larger goals of the NWS Weather Ready Nation.