PARAMETER-FREE AUTOMATIC SOLAR ACTIVE REGION DETECTION BY HERMITE FUNCTION DECOMPOSITION
- National Solar Observatory (NSO), 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)
We present a new method for the automated detection of sunspots and active regions (ARs) from full-disk observations of the photospheric Stokes vector. The algorithm relies on a Hermite function decomposition of observed Stokes polarization profiles as a function of position on the solar disk. This approach is unique in that it requires no user-defined tunable parameters, like intensity or magnetic field thresholds, and utilizes no information traditionally exploited by other detection schemes to signal the presence of an AR. It is truly a black-box approach, utilizing a self-consistent statistical analysis of the Hermite coefficients. We present the method and show the results of its application to Synoptic Optical Long-term Investigations of the Sun Vector Spectromagnetograph full-disk observations. Detection efficiency is presented for a one-month time series of daily photospheric observations, and we derive a skill-score for the method during this time period.
- OSTI ID:
- 22089803
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 203, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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