Variation of Supergranule Parameters with Solar Cycles: Results from Century-long Kodaikanal Digitized Ca ii K Data

Journal Article · Thu Jun 01 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA709D· OSTI ID:22663569

Chatterjee, Subhamoy; Mandal, Sudip; Banerjee, Dipankar ^[1]

---

1. Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India)

The Ca ii K spectroheliograms spanning over a century (1907–2007) from Kodaikanal Solar Observatory, India, have recently been digitized and calibrated. Applying a fully automated algorithm (which includes contrast enhancement and the “Watershed method”) to these data, we have identified the supergranules and calculated the associated parameters, such as scale, circularity, and 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-scale and small-scale magnetic fields on these structures and find a significantly different behavior of the supergranule parameters over solar cycles. These differences indicate intrinsic changes in the physical mechanism behind the generation and evolution of supergranules in the presence of small-scale and large-scale magnetic fields. This also highlights the need for further studies using solar dynamo theory along with magneto-convection models.

• OSTI ID: 22663569
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 841; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALGORITHMS
CALCIUM
CHROMOSPHERE
DATA ANALYSIS
EVOLUTION
GRANULATION
IMAGE PROCESSING
MAGNETIC FIELDS
MAGNETIC PROPERTIES
SIMULATION
SOLAR CYCLE
SPECTRA
SUN
WATERSHEDS