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Solar Topics

Solar Topics. Carl Luetzelschwab K9LA k9la@arrl.net. my web site is now at http://k9la.us. WWROF Webinars. Great way to learn about other aspects of Amateur Radio Recent ones The First Top Band DX Contest – the 1921 Transatlantic Test (by W3LPL)

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Solar Topics

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  1. Solar Topics Carl Luetzelschwab K9LA k9la@arrl.net my web site is now at http://k9la.us WWROF Webinar April 16, 2013 K9LA

  2. WWROF Webinars • Great way to learn about other aspects of Amateur Radio • Recent ones • The First Top Band DX Contest – the 1921 Transatlantic Test (by W3LPL) • Overview of Rule Changes for CQ WPX 2013 (by K5ZD) • CTU and Dayton Contest Activities (by K3LR) • Upcoming • April 26: What I’ve Learned in Two Decades of Terrain Assessment (by N6BV) • Don’t forget to support WWROF WWROF Webinar April 16, 2013 K9LA

  3. What We’ll Cover • Two Cycle 24 predictions • All the Cycle 24 predictions • Hemisphere asymmetry • Cycle 24 – two peaks? • SSN vs SF vs EUV • Are Sunspots Disappearing? • Disturbances from the Sun • References Mostly solar topics, with a tiny bit of propagation when relevant Cycle 24 update Butterfly diagrams Magnetograms Old sunspot data Missed an early cycle? Grand solar minimums Max vs previous min Our Cycle 24 prediction WWROF Webinar April 16, 2013 K9LA

  4. Cycle 24 Update Cycle 24 appears to have had a peak in early 2012 WWROF Webinar April 16, 2013 K9LA

  5. Butterfly Diagrams note asymmetry Hathaway image • Sunspots in a new cycle emerge at higher solar latitudes • Sunspots at the end of a cycle are near the solar equator WWROF Webinar April 16, 2013 K9LA

  6. Magnetograms first sunspot region of Cycle 24 • Sunspot region has magnetic field going out and coming back in • Measure magnetic field by Zeeman splitting • By convention, black is “in” and white is “out” • Magnetic fields are opposite from one cycle to the next • Magnetic fields are opposite in the hemispheres solar equator old sunspot region from Cycle 23 NASA photo Butterfly diagrams and magnetograms allow solar scientists to determine to which cycle (old or new) a sunspot region belongs WWROF Webinar April 16, 2013 K9LA

  7. A Cycle Is Really 22 Years Hoeksema, Sun, and Hayash image Cycle 21 max Cycle 22 max Cycle 23 max 1976 2012 WWROF Webinar April 16, 2013 K9LA

  8. Cycle 24 - Sunspots Sunspot data exhibits the same trends as the 10.7 cm solar flux data WWROF Webinar April 16, 2013 K9LA

  9. Old Sunspot Data • Counting sunspots is subjective • Human interpretation involved • Wolf 1849-1893, Wolfer 1876-1928, Brunner 1929-1944, Waldmeier 1945-1995 • Capability of telescope and cloud cover • Wolf’s equation: RZ = k (10G + S) • k is variable to bring different observers in line, G is number of groups, S is number of individual spots • Hoyt and Shatten asked the simple question “How good is the old data?” WWROF Webinar April 16, 2013 K9LA

  10. Group Sunspot Number • Realizing that counting individual sunspots (S) was likely the biggest challenge, they devised the Group Sunspot Number RG = k (12G) • The factor “12” scales RG to RZ • If you divide RG by RZ you should get 1.0 • That’s what they did, and here’s what it looks like WWROF Webinar April 16, 2013 K9LA

  11. RG / RZ Uncorrected Svalgaard & Cliver image RG / RZ less than 1.0 early on Two discontinuities – around 1946 and 1885 It looks like we’ve lived thru the highest solar activity in history WWROF Webinar April 16, 2013 K9LA

  12. Data Under Review • On-going Workshops • Sponsored by National Solar Observatory, the Royal Observatory of Belgium, and the Air Force Research Laboratory • Ultimate goal is to review and agree on the “true” sunspot number • Targeted to happen at a Fall 2013 Workshop in Europe WWROF Webinar April 16, 2013 K9LA

  13. RG / RZ Corrected Svalgaard & Cliver image Ratio of RG to RZ varies about 1.0 (can’t do much about the early scatter) Important implication: we’ve NOT lived thru the highest solar activity WWROF Webinar April 16, 2013 K9LA

  14. Did We Miss An Early Cycle? Alvestad image • Cycle 4 was extremely long • 1784 – 1798 • 14 years How could we have missed a cycle – the data looks very good WWROF Webinar April 16, 2013 K9LA

  15. Problem: Gaps In The Data Dalton Min xxx Min Hathaway image Much of the Cycle 4 data was assumed What really happened? WWROF Webinar April 16, 2013 K9LA

  16. Reconstructed Butterfly Diagram density of sunspots Cycle 4 start Cycle 5 start Suggests Cycle 4 may have really been only 10 years long Spots from a new cycle may have appeared in 1795/1796 WWROF Webinar April 16, 2013 K9LA

  17. Auroral Activity Cycle 5 start Cycle 4 start Indicates an increase in auroral activity around 1796 WWROF Webinar April 16, 2013 K9LA

  18. Missed Cycle - Conclusion • We may have missed an early cycle • It was a small one prior to the Dalton Minimum • Doesn’t appear to be any discussion to further review and correct this • It would be difficult to re-number the cycles after Cycle 4 • If anything is done, best to call it Cycle 4a WWROF Webinar April 16, 2013 K9LA

  19. Grand Solar Minimums • No reliable sunspot data from long ago • Use proxies for solar activity • Carbon-14 in tree rings • High carbon-14 means low solar activity • Low carbon-14 means high solar activity • Beryllium-10 in ice cores • Identical trends to carbon-14 • Gives us a broad view of solar activity WWROF Webinar April 16, 2013 K9LA

  20. Inferred Grand Minimums xxx We’ll likely go through another Grand Minimum – questions are “when?” and “what magnitude?” WWROF Webinar April 16, 2013 K9LA

  21. Duration of Solar Minimum recent solar min (56 months) Cyclic in nature – started with short duration solar mins WWROF Webinar April 16, 2013 K9LA

  22. Maximum of Solar Cycle Also cyclic in nature – started with large solar cycles WWROF Webinar April 16, 2013 K9LA

  23. Max and Duration of Previous Min They are out of phase WWROF Webinar April 16, 2013 K9LA

  24. The Correlation Suggests . . . Our prediction for Cycle 24 is a smoothed sunspot number of ~ 80 Translates to a smoothed 10.7 cm solar flux of ~ 130 WWROF Webinar April 16, 2013 K9LA

  25. Official Prediction - ISES • ISES has not changed their prediction since mid 2009 • Prior to mid 2009, they carried two predictions • One high, one low http://www.swpc.noaa.gov/SolarCycle/ WWROF Webinar April 16, 2013 K9LA

  26. Official Prediction - MSFC MSFC continues to revise its prediction based on actual results http://solarscience.msfc.nasa.gov/predict.shtml WWROF Webinar April 16, 2013 K9LA

  27. A Comment About Predictions • Over 60 predictions for Cycle 24 • From 40 to 180 (smoothed sunspot number) • Several are going to be “right” • Many more will be wrong • We still don’t understand the process in the Sun that causes solar cycles WWROF Webinar April 16, 2013 K9LA

  28. Hemisphere Asymmetry Svalgaard & Kamide image If the southern hemisphere gets going . . . . Sunspot emergence not symmetrical The northern hemisphere has dominated Cycle 24 WWROF Webinar April 16, 2013 K9LA

  29. Cycle 24 – Two Peaks? Great video - http://www.youtube.com/watch?v=6j4bl57D_1U Dr. Presnell of the Goddard Space Flight Center believes Cycle 24 will have two peaks Second peak from southern hemisphere Cites Cycle 14 as similar to Cycle 24 WWROF Webinar April 16, 2013 K9LA

  30. Recent Two-Peaked Cycles Cycles 19, 20, and 21 didn’t have a discernible second peak Cycles 22 and 23 had two peaks Reminder – official peak is in terms of a smoothed solar index WWROF Webinar April 16, 2013 K9LA

  31. Early Two-Peaked Cycles Cycle 5 Cycle 9 Alvestad images Cycle 11 Cycle 12 Would be nice if Cycle 24 did something like Cycle 23 or 12 WWROF Webinar April 16, 2013 K9LA

  32. SSN vs 10.7 cm SF vs EUV • Reminder – sunspots and 10.7 cm solar flux are proxies for true ionizing radiation • True ionizing radiation is at wavelengths from roughly 0.1 – 100 nanometers • 0.1 – 1 nm and 121.5 nm for the D region • 1 – 10 nm for the E region • 10 – 100 nm for the F2 region • Important wavelength for F2 region ionization is around 30 nm • Contributes to about 2/3 of the electron density WWROF Webinar April 16, 2013 K9LA

  33. Daily Values of 26 - 34 nm correlation sunspots vs EUV .6283 10.7 cm sf vs EUV .7492 Daily 10.7 cm solar flux correlates better to daily EUV But don’t throw out sunspots WWROF Webinar April 16, 2013 K9LA

  34. Variation of the Ionosphere Neither EUV, 10.7 cm solar flux nor sunspots correlate well to the day-to-day variation of the ionosphere F2 region ionization depends on solar radiation, geomagnetic field activity, and events in lower atmosphere coupling up to ionosphere WWROF Webinar April 16, 2013 K9LA

  35. Another Interesting Correlation Up to the first peak of Cycle 23, smoothed sunspot number and smoothed 10.7 cm solar flux were extremely well correlated WWROF Webinar April 16, 2013 K9LA

  36. But After the Peak . . . We now see less sunspots for a given 10.7 cm solar flux WWROF Webinar April 16, 2013 K9LA

  37. Are Sunspots Disappearing? • July 2009 paper by W. Livingston and M. Penn • Sunspots are visible when their magnetic field strength is > 1500 gauss • Extrapolating the linear trend line says no sunspots will be visible around the end of the decade • Latest data presented by Dr. Leif Svalgaard (thru early 2013) shows the decreasing trend is continuing most recent data Livingston & Penn image WWROF Webinar April 16, 2013 K9LA

  38. What’s Happening to EUV? EUV data from www.usc.edu/dept/space_science/semdatafolder/long/daily_avg/ EUV is holding up in spite of sunspots disappearing Other measurements (next slide) confirm this WWROF Webinar April 16, 2013 K9LA

  39. Other Measurements Why 6m was so good around Nov 2001 This data suggests that sunspots are the only parameter that is disappearing Lukianova & Mursula images WWROF Webinar April 16, 2013 K9LA

  40. Another Minimum • A grand solar minimum is a period when sunspots disappear • But since it appears that EUV may still be there, maybe a grand solar minimum will not be as bad as we think • This is radical thinking Archibald image • Only answer is to wait and see what happens to EUV with respect to the disappearing sunspots WWROF Webinar April 16, 2013 K9LA

  41. Disturbances from the Sun visit http://www.swpc.noaa.gov/NOAAscales/ to learn more about G, S, and R WWROF Webinar April 16, 2013 K9LA

  42. Mitigation for Disturbances No guarantees here – just suggestions WWROF Webinar April 16, 2013 K9LA

  43. References • The Solar Cycle, David H. Hathaway, NASA, Marshall Space Flight Center, Huntsville, AL, March 2010 • A History of Solar Activity over Millennia, Ilya G. Usokin, Sodankyla Geophysical Observatory, University of Oulu, Finland, October 2008 • Solar Cycle Characteristics Examined in Separate Hemispheres: Phase, Gnevyshev Gap, and Length of Minimum, A. A. Norton and J. C. Gallagher, James Cook University, Townsville, Australia, January 2010 • http://www.solen.info/solar/ • http://www.leif.org/research/ • Temporal Changes in Sunspot Umbral Magnetic Fields and Temperatures, M. J. Penn, W. Livingston, National Solar Observatory, The Astrophysical Journal, 649, L45-L48, September 2006 WWROF Webinar April 16, 2013 K9LA

  44. References – con’t • Another Maunder Minimum?, Leif Svalgaard, Stanford University, November 2012 • Reconciling Group and International Sunspot Numbers, Leif Svalgaard, Stanford University, Edward W. Cliver, Air Force Research Laboratory, September 2012 • Disappearance of Visible Spots, Leif Svalgaard, Stanford University, September 2012 • Solar Activity – Past, Present, and Future, Leif Svalgaard, Stanford University, October 2012 • Symmetric Solar Polar Field Reversals, Leif Svalgaard, Stanford Univeristy, Yohsuke Kamide, Nagoya University, December 2012 • Changed relation between sunspot numbers, solar UV/EUV radiation and TSI during the declining phase of solar cycle 23, R. Lukianova, K. Mursula, Journal of Atmospheric and Solar-terrestrial Physics, 73 (2011), pp 235-240 WWROF Webinar April 16, 2013 K9LA

  45. Summary We covered a lot of material – the following are what I consider important • Cycle 24 has a good chance of having a second peak – will help prolong propagation on the higher bands • Right now the few Cycle 25 predictions are for another low solar cycle • We’ll enter another grand solar minimum one of these days • Don’t know when or magnitude • But it may not result in the demise of the ionosphere • Best to use the smoothed 10.7 cm solar flux in your propagation predictions WWROF Webinar April 16, 2013 K9LA

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