Case study: Visualizing ocean flow vertical motions using Lagrangian-Eulerian time surfaces

Ocean model simulations commonly assume the ocean is hydrostatic, resulting in near zero vertical motion. The vertical motion found is typically associated with the variations of the thermocline depth over time, which are mainly a result of the development and movement of ocean fronts, eddies, and internal waves. A new technique, extended from Lagrangian-Eulerian Advection, is presented to help understand the variation of vertical motion associated with the change in thermocline depth over time. A time surface is correctly deformed in a single direction according to the flow. The evolution of the time surface is computed via a mixture of Eulerian and Lagrangian techniques. The dominant horizontal motion is textured onto the surface using texture advection, while both the horizontal and vertical motions are used to displace the surface. The resulting surface is shaded for enhanced contrast. Timings indicate that the overhead over standard 2D texture advection is no more than 12%.