Models of ocean conditions are numerical predictions of what the ocean is like at a given time, based on inputs and known physics. The inputs are observations from satellites, moorings, tidal gauges, high-frequency radar stations, and buoys, among other sources. This information is collected daily and fed into the model. The model takes this new data, along with model estimates from the previous calculation, and applies equations of fluid physics to calculate how the conditions at a site will change over a given time period. To describe the conditions of a body of water, the model fills that three-dimensional body with millions of points arrayed in a 3-D grid. It calculates the conditions at each point, based on the point’s previous conditions, observations near that point, and the amount of time from the last calculation. All these point calculations are the model output, and are often visualized in a 3-D map of the water body.