A Web Product for High Frequency Radar Surface Current Observations and Tidal Current Predictions

High frequency (HF) Radar provides one of the most effective means to observe large spatial areas of surface currents in near real-time. The coastlines and estuaries of the U.S. have significant HF Radar coverage as there are presently over 130 systems operated by a variety of academic institutions, government and private organizations. The availability and standardization of these data have enabled the development of a new NOAA web product which combines HF Radar observations and tidal current predictions in a simple-to-use interface. This product is presently available for Chesapeake Bay and San Francisco Bay. Here we present aspects of the development of this product, including data processing, quality control and results of the harmonic analysis used to generate the tidal current predictions from HF Radar observations. Interesting considerations with the harmonic analysis include the influence of missing data on the resulting predicted currents as well as the spatial variability in harmonic constituents and residual non-tidal energy. We also present some ongoing and future product enhancements including the expansion to additional locations and the potential for a statistical prediction of short-term non-tidal variability. This NOAA HF Radar web product has benefits for marine navigation, search and rescue, oil spill response and the recreational boating community among others.