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%.

[1]  Theo van Walsum,et al.  Fluid Flow Visualization , 1991, Focus on Scientific Visualization.

[2]  Brian Cabral,et al.  Imaging vector fields using line integral convolution , 1993, SIGGRAPH.

[3]  Jarke J. van Wijk.  Flow visualization with surface particles , 1993, IEEE Computer Graphics and Applications.

[4]  Cláudio T. Silva,et al.  Flow Surface Probes for Vector Field Visualization , 1994, Scientific Visualization.

[5]  Frits H. Post,et al.  Three ways to show 3D fluid flow , 1994, IEEE Computer Graphics and Applications.

[6]  Robert J. Moorhead,et al.  AGP: ocean model flow visualization , 1995, IEEE Computer Graphics and Applications.

[7]  Robert J. Moorhead,et al.  Visualizing vector information in ocean environments , 1995, 'Challenges of Our Changing Global Environment'. Conference Proceedings. OCEANS '95 MTS/IEEE.

[8]  Nelson Max,et al.  Flow visualization using moving textures , 1995 .

[9]  Kelly P. Gaither,et al.  Interactive visualization of ocean circulation models , 1996, Proceedings of Seventh Annual IEEE Visualization '96.

[10]  Hans-Peter Seidel,et al.  Applications of pixel textures in visualization and realistic image synthesis , 1999, SI3D.

[11]  Hans Hagen,et al.  Visualizing planar vector fields with normal component using line integral convolution , 1999, Proceedings Visualization '99 (Cat. No.99CB37067).

[12]  Zhifan Zhu,et al.  Extracting and Visualizing Ocean Eddies in Time--Varying Flow Fields , 2000 .

[13]  Christopher R. Johnson,et al.  A level-set method for flow visualization , 2000, Proceedings Visualization 2000. VIS 2000 (Cat. No.00CH37145).

[14]  Thomas Ertl,et al.  Hardware-Accelerated Visualization of Time-Varying 2D and 3D Vector Fields by Texture Advection via Programmable Per-Pixel Operations , 2001, VMV.

[15]  Gordon Erlebacher,et al.  Lagrangian-Eulerian advection for unsteady flow visualization , 2001, Proceedings Visualization, 2001. VIS '01..

[16]  Jarke J. van Wijk,et al.  Image based flow visualization , 2002, ACM Trans. Graph..