Automatic Detection of Magnetic delta in Sunspot Groups

作者：Padinhatteeri Sreejith^*; Higgins Paul A; Bloomfield D Shaun; Gallagher Peter T

来源：Solar Physics, 2016, 291(1): 41-53.

DOI：10.1007/s11207-015-0808-7

• Active region
• Sunspots
• Mt. Wilson classification
• delta-Spots

Large and magnetically complex sunspot groups are known to be associated with flares. To date, the Mount Wilson scheme has been used to classify sunspot groups based on their morphological and magnetic properties. The most flare-prolific class, the delta sunspot group, is characterised by opposite-polarity umbrae within a common penumbra, separated by less than 2 degrees. In this article, we present a new system, called the Solar Monitor Active Region Tracker-Delta Finder (SMART-DF), which can be used to automatically detect and classify magnetic delta s in near-realtime. Using continuum images and magnetograms from the Helioseismic and Magnetic Imager (HMI) onboard NASA's Solar Dynamics Observatory (SDO), we first estimate distances between opposite-polarity umbrae. Opposite-polarity pairs with distances of less that 2 degrees are then identified, and if these pairs are found to share a common penumbra, they are identified as a magnetic delta configuration. The algorithm was compared to manual delta detections reported by the Space Weather Prediction Center (SWPC), operated by the National Oceanic and Atmospheric Administration (NOAA). SMART-DF detected 21 out of 23 active regions (ARs) that were marked as delta spots by NOAA during 2011 - 2012 (within +/-60 degrees longitude). SMART-DF in addition detected five ARs that were not announced as delta (s)pots by NOAA. The near-realtime operation of SMART-DF resulted in many ds being identified in advance of NOAA's daily notification. SMART-DF will be integrated into SolarMonitor (www.solarmonitor.org) and the near-realtime information will be available to the public.

• 出版日期2016-1