Lorraine Heilman

and 2 more

NOAA/National Ocean Service’s (NOS) Center for Operational Oceanographic Products and Services (CO-OPS) provides users with real-time currents at more than sixty stations, currents predictions at thousands of historic and active stations, and operational currents nowcast and near-term forecast information in navigable estuaries, harbors, rivers, and coastal regions of the United States as an integral part of its safe navigation mission. CO-OPS performs at least one current survey each year to update currents predictions in regions of particular interest to stakeholders. NOS’ Operational Forecast Systems (OFS) operate and maintain fully 3-D hydrodynamic models that provide regional nowcast and forecast (48-60 hours) guidance for water levels, currents, salinity, and temperature. By combining the information available from real-time observations, current surveys, historic current predictions, and OFS output, both the tidal current predictions and the OFS forecast products can be improved. Tidal current predictions are traditionally generated based on analysis of at least one month of six-minute observation data obtained from a physically deployed current meter using harmonic least squares techniques to resolve tidal constituents. By using longer time series and traditional techniques combined with additional statistical methods, a more accurate representation of the tidal flow and a more exact match to the shape of the tidal current curve is obtained. By applying these methods to long-term OFS output at locations where long-term physical observations also exist, tidal current predictions based on model data within the model domain can be verified. Once verified, the number of available “virtual stations” exponentially increases the repository of tidal current predictions. Users can choose any location of interest and receive tidal current predictions that can be incorporated into integrated, user-friendly navigation products and tools. We will evaluate this technique in the lower Chesapeake Bay using output from the Chesapeake Bay Operational Forecast System (CBOFS) and real-time currents data.