Application of Real-Time Data Systems to the Forecasting of Water Level and Circulation

The forecasting of water levels and currents has generally been limited to tide and tidal current prediction, which can be done quite accurately because of the well known astronomical periodicities involved. Forecasting nontidal changes in water levels and currents, i.e., those due to changes in wind, atmospheric pressure, and river discharge, presents more of a problem, depending as it does on the forecasting of meteorological phenomena. The use of real-time data acquisition systems improves the accuracy of such forecasts, providing both the point of departure for the forecast as well as the means by which to assess the performance of the forecast (in real time). Possible real-time systems range from a single instrument providing data for a statistical forecasting model to a large numerical hydrodynamic model driven by real-time/forecast data; the choice depends upon the needs of the user for which they are designed. Generally, nontidal water level forecasting has been limited to storm surge forecasting (based on expected winds from a particular storm system) and has been done primarily for the timely issuance of coastal flood warnings. There are, however, other applications for forecast water levels and currents, during less extreme meteorological conditions, that require enough accuracy that tide and tidal current predictions alone are not adequate. Such forecasts enable large cargo vessels and tankers to make maximum use of available channel depths, leading to safer and more economical commerce; forecast circulation allows for safer maneuvering of these vessels in harbor entrances and turning basins. Forecast circulation is critical to successful search and rescue operations and oil spill cleanup. Other potential applications include optimum track ship routing, water quality forecasts, and military applications.