Authors: D.A. Haber, B.W. Hindman, J. Toomre; M.J. Thompson; R.S. Bogart
Affiliation: JILA, University of Colorado; Imperial College, London; Stanford
University, CSSA-HEPL
There are now several years of SOI-MDI Dynamics data taken during the declining phase of the solar cycle when large coronal holes are prevalent. Many of these coronal holes crossed disk center where they were readily observed with local helioseismology techniques. We have used ring analysis to assess differences between large-scale flows inside coronal holes with those outside the holes. We have used time-distance methods to examine in more detail the correlation of small-scale subsurface flows with the presence of coronal hole boundaries. We discuss whether equator-extending coronal holes are correlated with or modify meridional circulations. We also report on how the local rotation rate varies within the near-surface shear layer below coronal holes. HMI onboard SDO will give us continuous high-resolution observations that will allow us to view coronal holes over the many rotations that they survive, enabling a better understanding of the interaction of coronal holes with subphotospheric flows.