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V.V. Zharkova 1 , and S. Zharkov 2 1- Bradford University, 2 – Sheffield University

Understanding solar activity using statistical properties of solar features in SFCs and flare occurrences. V.V. Zharkova 1 , and S. Zharkov 2 1- Bradford University, 2 – Sheffield University http://solar.inf.brad.ac.uk. Catalogue Description (Zharkova et al., 2005, ASR).

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V.V. Zharkova 1 , and S. Zharkov 2 1- Bradford University, 2 – Sheffield University

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  1. Understanding solar activity using statistical propertiesof solar features in SFCs and flare occurrences V.V. Zharkova1, and S. Zharkov2 1- Bradford University, 2 – Sheffield University http://solar.inf.brad.ac.uk

  2. Catalogue Description (Zharkova et al., 2005, ASR) http://solar.inf.brad.ac.uk • Observational Parameters: • Date of observation, resolution; determined quiet sun intensity; • Feature Parameters: • Gravity center (proj & Carrington), area, diameter, umbra size, bounding rectangle, intensity statistics, magnetic information • Raster Scans (bounding rectangle mask): • reconstructed: pixel values equal to 0 corresponding to quiet Sun, 1 to penumbra, 2 to umbra • Sunspot Catalogue (from 1996-05-19 19:08:35 to 2005-05-31 19:51:32) • About 10000 observation processed • ~370000 sunspots and 100 000 ARs stored • SSW software: • Catalogue Search -> VOTable -> IDL SSW -> features reconstructed, over plotted

  3. Sunspot Detection (Zharkov et al., 2005, Eurasip J.) detected edges & low intensity regions => <= original image <ROI result >

  4. Automatically detected active regions with region growing (left) and the ARs from Big Bear Solar Observatory (right)

  5. Search page sample

  6. SFC Example

  7. Sunspot areas comparison USAF SOON / SFC – 96% correlation

  8. N-S asymmetry in daily s/s areas

  9. Daily areas covered by ARs in N-S hemispheres

  10. Daily mean intensities of active regions in 1996-2005

  11. North South Asymmetry(averaged by 170 days) (N-S)/(N+S) (ss –top, ar –bottom)

  12. North South AsymmetryCumulative Area (Solar Cycle 23)ss –left, ar -right Temmer, Veronig Hanslmeier, A&A 2001, SoPh 2003

  13. North-South asymmetry in cumulative areas (s/s left and ar right)

  14. Variations of Flare numbers and sunspot areas in cycle 23

  15. Sunspot statistics Cumulitative areas: North – solid blue line, South – dashed navy line Asymmetry in cumulitative areas averaged by 4 month (purple), 1 year (navy) and 3 years (blue)

  16. Flare statistics: N-S and W-E asymmetriesJoshi ad Pant, 2005; Zharkova and Zharkov, 2006 Cumulitative areas: North – blue line, South – navy line Cumulitative areas: West – purple line, East – pink line

  17. Latitudinal distributions flare occurrences

  18. Sunspot and flare butterfly diagrams in the cycle 23

  19. Latitude distributions of flare occurrences (averaged by 30,180,360 & 1080 days)

  20. Flare latitude occurrences in the cycle 23 – correlation with AR N-S asymmetry (0.85)

  21. Longitude distributions of flare occurrences averaged by 30,90,180 & 1080 days –active longitude of 200o

  22. Sunspot active longitudes

  23. Butterfly diagram for flare occurrences in cycle 23 (L=200o, =15o, 4o, -5o, -15o)

  24. Force-free global magnetic configuration -17/03/02 (courtesy of Y.Yan, 2005)

  25. Conclusions • In the cycle 23 solar flare occurrences show a moderate (0.62) correlation with sunspot area variations and higher with AR areas (0.81) • N-S asymmetry is a common pattern in s/s and AR (plages) areas and flare occurrences with different levels of periodicity (2 and 9 (11?) years) • Flare latitudinal distributions show maxima at the latitudes of about 15-20o • Flare occurrences averaged by a year show the ‘active’ latitudes on 5o, 15o and -15o and -5o • Essential W-E asymmetry in the cumulitative flare occurences • This W-E asymmetry is distinctly seen in the averaged flare longitudinal distributions at the longitude of 200o.

  26. Thank you!

  27. Future Planshttp://solar.inf.brad.ac.uk • Investigate data further • Database relatively small (for long-term statistics), but will only grow • Interested in additional input – possible statistics to be extracted, offered, other data sources, other features & feature parameters • Filling the data gaps & periodogram analysis • Latitude and longitude distributions • Extend the statistical analysis of the current cycle and possible links with solar dynamo models • Sunspot classification into groups • Extraction of Sunspot Group tilt and its variation with the Solar Cycle • More ????

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