Comparison Of Solar Surface Features In HMI Images And Mount Wilson Images Found By The Automatic Bayesian Classification System AutoClass
Abstract
The Bayesian automatic classification system AutoClass has been applied to daily solar magnetogram and intensity images taken at the 150 Foot Solar Tower at Mount Wilson to find and identify classes of solar surface features which are associated with variations in total solar irradiance (TSI) and, using those identifications, to improve modeling of TSI variations over time. (Ulrich, et al, 2010) AutoClass does this by a two step process in which it: (1) finds, without human supervision, a set of class definitions based on specified attributes of a sample of the image data pixels, such as magnetic field and intensity in the case of MWO images, and (2) applies the class definitions thus found to new data sets to identify automatically in them the classes found in the sample set. HMI high resolution images embody four observables-magnetic field, continuum intensity, line depth and line width-in contrast to MWO's two-magnetic field and intensity. In this study, we apply AutoClass to the HMI image observables to derive solar surface feature classes and compare the characteristic statistics of those classes to the MWO classes. The ability to categorize automatically surface features in the HMI images holds out the promise of consistent, relatively quick and manageable analysis of the large quantity of data available in these images. Given that the classes found in MWO images using AutoClass have been found to improve modeling of TSI, application of AutoClass to the more complex HMI images should enhance understanding of the physical processes at work in solar surface features and their implications for the solar-terrestrial environment. Ulrich, R.K., Parker, D, Bertello, L. and Boyden, J. 2010, Solar Phys. , 261 , 11.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMSH13A2244P
- Keywords:
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- 7536 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Solar activity cycle;
- 7537 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Solar and stellar variability;
- 7538 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Solar irradiance;
- 7594 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Instruments and techniques