Synoptic Subsurface Flow Maps
For a specific Carrington Rotation this package will calculate the synoptic flow map and the synoptic residual flow map, as well as the fluid divergence, vorticity and vertical velocity at the specified depth (from 2 to 15 Mm). These are done using velocity inversion data from the GONG website, as well as the synoptic magnetogram from either the GONG or MDI website. An example of the synoptic flow map and the synoptic flow residuals is shown below. It is interesting to look at flows surrounding active regions and for this the residuals are more relevant than the actual flow maps.
Komm et al. 2004 (ApJ) paper describing the ring diagram method, how the flows are calculated and the physical fluid descriptors.
The HELAS Ring Diagram Pipeline webpage.