Relatively constant directional flows of large water masses, which can be driven by a variety of dynamic forces. Distributions are observations of current speed and flow volume, as a function of location, time, and depth, and they include maps of ocean current climatology generated from oceanographic and weather observations, analysis of other driving forces, hydrodynamic theory, and numerical models. Assessments evaluate technology, locations, and profitability for using ocean currents to generate energy; they also evaluate effects of currents on biological resources and on other uses such as transportation or the extraction of resources. Predictions are the results of models or projections of future currents, energy potential, effects, and risks; these data include predicted changes due to economic, regulatory, technological, and environmental changes.