Flow structures of Jupiter's Great Red Spot extracted by using optical flow method

Abstract

The flow structures of Jupiter's Great Red Spot (GRS) are studied based on a highresolution velocity field extracted from the Galileo 1996 cloud images of the GRS by using the physics-based optical flow method. The mean transverse velocity profile across the anti-cyclonic near-elliptical collar of the GRS is obtained. The flow structures in the relatively quiescent inner region enclosed by the high-speed collar are revealed at a coarse-grained level. The cyclonic source node in the inner region is identified that is directly associated with the observed cyclonic rotation near the center of the GRS, and its significance in the maintenance of the GRS is explored by using a topological constraint. C 2012 American Institute of Physics.

Geodesic Transport Barriers in Jupiter's Atmosphere: A Video-Based Analysis

“…Later improvements involved two-dimensional extensions and coarse-to-fine iteration schemes [8]. Recent approaches add an advection equation to the procedure [3], or apply the idea of an optical flow [35]. Similar methods have also been applied to image sequences of other planets such as Saturn [46], Uranus and Neptune [31], and the Earth [32].…”

Comparison between optical flow and cross-correlation methods for extraction of velocity fields from particle images

“…Further, these equations are recast into the physics-based optical flow equation in the image plane, where the optical flow is proportional to the light-ray-pathaveraged velocity of fluid (or particles) weighted in a relevant field quantity like dye concentration, fluid density or particle concentration. Using the optical flow method, Liu et al (2012) have studied the unique intrinsic flow structures of Jupiter's Great Red Spot (GRS) based on highresolution velocity fields extracted from the NASA Galileo 1996 cloud images of the GRS.…”

OpenOpticalFlow: An Open Source Program for Extraction of Velocity Fields from Flow Visualization Images

“…Optical flow computation can be conducted in a PC with Matlab to extract velocity fields at a spatial resolution of one vector per a pixel. The optical flow method has been used in some challenging flow measurements in which the traditional cross-correlation method in PIV could not provide sufficient high-resolution velocity fields in large domains [7][8][9][10][11][12]. Although there are research optical flow programs developed by different groups, an easy-to-use open source program is still lacking for non-expert users in various settings of fluid-mechanic applications.…”

“…However, within a considerable range of the Lagrange multipliers, the solution is not significantly sensitive to its selection. Simulations based on a synthetic velocity field for a specific measurement could be carried out to determine the Lagrange multiplier by using an optimization scheme [8].…”

“…Physically, the optical flow is proportional to the light-ray-path-averaged velocity of fluid (or particles) weighted in a relevant field quantity like dye concentration, fluid density or particle concentration. The optical flow method has been used to study the flow structures of Jupiter's Great Red Spot (GRS), impinging jets, and laser-induced underwater shock wave [8][9][10][11]. A mathematical analysis of the variational solution of the optical flow and an iterative numerical algorithm are given by Wang et al [12].…”