IOP Publishing, Journal of Physics: Conference Series, (440), p. 012022, 2013
DOI: 10.1088/1742-6596/440/1/012022
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We study synoptic maps of solar subsurface flows covering six Carrington rotations (2050 to 2055). The subsurface flows are determined with a ring-diagram analysis of GONG high-resolution Doppler data. We identify the locations of coronal holes in synoptic maps of EUV images at 195Å from the EIT instrument and determine the characteristics of associated subsurface flows. We study two long-lived coronal holes that are present during this epoch. We find that large-scale patterns are present in the subsurface flows but appear to be unrelated to these coronal holes. The horizontal subsurface flows associated with the two long-lived coronal holes are weakly divergent (upflows) with small cyclonic vorticity. These flows are thus similar to subsurface flows of quiet regions with regard to the vertical flows and similar to flows of active regions with regard to vorticity. © 2013 Published under licence by IOP Publishing Ltd.