The color shows the salinity of surface waters in south Puget Sound. The model is a high-resolution (100 m grid) sub-model nested inside the larger LiveOcean domain.
The movie has a panel at the bottom that shows time. The tide is evident in the twice-a-day variation of the sea surface height. Daytimes are shown as the thick yellow lines on the horizontal axis. Winds are shown by an arrow in the middle of the map, with the scale given by the circle.