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G.W. Simon (AFRL, NSO/Sunspot, Emeritus Research Services), R.A. Shine (Lockheed Martin Solar and Astrophysical Laboratory)
Using a unique set of white-light images taken by the Transition Region and Corona Explorer (TRACE) satellite over a 7 day period in April 2000, we investigate the properties and evolution of supergranulation. A 384x384 arcsec area of the solar photosphere was observed as it rotated from Stonyhurst longitude 45E to 45W. Granulation is well defined in these images which were taken at a 60s cadence for most of the 7 days. Hence we are able to use local correlation tracking (LCT) with sufficient spatial and temporal resolution to track both mesogranules and supergranules. Improved techniques for LCT are discussed and compared.
Divergence and other parameters derived from flow maps are used to identify and accurately trace supergranular boundaries and tessellate the image areas into distinct supergranules as well as smaller areas with less coherent flow patterns. We have used these to derive sizes, lifetimes, and other properties of supergranules. Motivated by recent work of Rast, Lisle, and Toomre (2004), and Lisle, Rast, and Toomre (2004), we also present results comparing the rotational rate of the supergranular and mesogranular patterns and N/S alignments of these features.
This work was supported by NASA contract NAS5-38099, the Air Force Research Laboratory, and the National Solar Observatory.
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Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.