Assimilation of Wind Retrievals from a Network of Coastal High-Frequency Radars with Bistatic Configuration

Near-surface wind retrievals off the coast of Long Island were obtained from a coastal high-frequency (HF) radar network from May 1-22, 2022. These retrievals used HF radar Doppler spectra observations, in conjunction with an HF radar forward and adjoint model and the Simulating WAves Nearshore (SWAN) model. Previous studies have demonstrated the capability of retrieving near-surface winds from coastal HF radar networks, highlighting its potential benefit for numerical weather prediction. This study used observations from a single HF radar bistatic receiver collecting Doppler spectra from itself as well as three bistatic transmitters located around the New York/New Jersey Bight. To evaluate the impact of these winds in numerical weather prediction, hourly HF radar wind retrievals were assimilated in the Navy’s Coupled Ocean/Atmosphere Mesoscale Prediction System® (COAMPS) using the COAMPS-4DVar (4D-variational). We present an evaluation of the quality of the HF radar wind retrievals during this case study and their impact on forecast using the forecast sensitivity to observation impact (FSOI) diagnostic and an observing system experiment (OSE).