Variation of Supergranule Parameters With Solar Cycles: Results From Century-Long Kodaikanal Digitized Ca II K Data

Abstract

The century-long (1907-2007) Ca II K spectroheliograms from Kodaikanal Solar Observatory, India, has recently been digitised and calibrated. Applying a fully-automated algorithm (which includes contrast enhancement and 'Watershed method') on this data, we have identified the supergranules and calculated the associated parameters, such as scale, circularity, fractal dimension. We have segregated the quiet and active regions and obtained the supergranule parameters separately for these two domains. In this way, we have isolated the effect of large and small scale magnetic fields on such structures and find significantly different behavior of the supergranule parameters over solar cycles. Such differences indicate the intrinsic changes in the physical mechanism behind generation and evolution of supergranules in presence of small and large scale magnetic fields. This also highlights the need for further studies using solar dynamo theory along with magneto-convection models.

24 pages, 10 figures, accepted for publication in ApJ

References in corpus (1)

• Butterfly Diagram and Carrington Maps for Century-Long Ca II K Spectroheliograms from Kodaikanal Observatory

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