A Real-Time Experiment Using PCTides 2.0

Abstract : A real-time test of the Naval Research Laboratory's (NRL) globally relocatable tidal prediction system (PCTides 2.0) was performed during the naval exercise Autonomous Underwater Vehicle Fest 2005 (AUVFest 2005) that occurred June 6-16, 2005 in the Puget Sound, Washington, area. AUVFest 2005 was sponsored by the Office of Naval Research (ONR) and involved two weeks of intensive AUV experimentation and demonstration. PCTides 2.0 consists of a barotropic ocean model designed to forecast tidal currents and sea-level water elevations on or near continental shelves. The system is set up to run on a PC or UNIX platform with a global database of bathymetry, boundary conditions, and tidal station data for assimilation purposes. During AUVFest 2005, PCTides 2.0 predicted water elevations and tidal currents using a series of grids with increasing resolution. Tidal forecasts from the 1.5-km nest are presented here. The grids were run daily, producing a 5-day forecast of tidal height and currents with graphical results posted to the Naval Oceanographic Office (NAVOCEANO) WEBSITE. During the exercise, the PCTides 2.0 tidal phase forecasts provided the optimum dive window for an AUV recovery exercise and a successful recovery of a bottom "crawler" stuck in the mud. Feedback from the divers was that the modeled tidal phase forecasts were "dead on."