Evaluation of WERA HF radar observations: currents, winds and waves

Abstract

Within the Straits of Florida, a strongly sheared western boundary current interacts with waves and wind to produce a complex environment that is difficult to forecast, and makes in situ data collection at the ocean surface challenging. For these reasons, ensuring accurate remote measurements of current velocity, significant wave height and wind direction from high frequency (HF) radar is an ongoing priority. In this study, we deploy a subsurface mooring in the HF radar footprint that is equipped with Nortek’s Acoustic Wave and Current Profiler (AWAC), and collect wind data from a nearby meteorological station. We evaluate the HF radar measurements through a comparison with these independent in situ datasets. With regard for their sampling differences, our results show that the remote and in situ instruments compared favorably. For the majority of the deployment, the current velocity exceeded 2 m s-1 at the mooring; this created excessive drag on the buoy leading to instrument tilt. For this reason, the mooring design and instrument performance are examined in closer detail. These preliminary results demonstrate the importance of collecting remote high resolution data from HF radar over the Straits of Florida.