1. Solar Cycle 24 Carl Luetzelschwab K9LA k9la@arrl.net QCWA Chap 36 April 2012 K9LA

2. What We’re Going to Cover Recent solar minimum Predictions for Cycle 24 Cycle 24 status Four FAQs QCWA Chap 36 April 2012 K9LA

3. Recent Solar Minimum QCWA Chap 36 April 2012 K9LA Minimum between Cycle 23 and 24 very unusual for our lifetimes

4. All Solar Minimum Periods QCWA Chap 36 April 2012 K9LA But not all that unusual for all 23 solar minimum periods Note cyclic nature of data

5. All Solar Maximums Note cyclic nature of this data, too Is there a correlation between duration of solar min and next max? QCWA Chap 36 April 2012 K9LA Average ~ 115

6. Next Max vs Previous Min Suggests Cycle 24 will be below average – 56 months (from previous slide) = 85 And maybe the next couple cycles, too QCWA Chap 36 April 2012 K9LA

7. Latest Prediction from MSFC Nominal max of 61 Uncertainty in prediction puts high side at 87 QCWA Chap 36 April 2012 K9LA MSFC is the Marshall Space Flight Center in Huntsville, AL [ http://solarscience.msfc.nasa.gov/predict.shtml ]

8. Latest Predictions from ISES QCWA Chap 36 April 2012 K9LA in terms of sunspot numberin terms of 10.7 cm solar flux ISES is the International Space Environment Service – a service used by the Space Weather Prediction Center of NOAA [http://www.swpc.noaa.gov/SolarCycle/ ] Don’t forget that the sunspot number and 10.7 cm solar flux are proxies for the true ionizing radiation

9. Latest Data for Cycle 24 The recent slowdown in the smoothed sunspot number may just be a normal “leveling off” as seen in other cycles April monthly mean is likely to be higher than March monthly mean Expect the smoothed sunspot number to again increase QCWA Chap 36 April 2012 K9LA

10. When Are The Higher Bands Open? 15-Meters: F 2 when the smoothed sunspot number > 25 – We’re already there 12-Meters: F 2 when the smoothed sunspot number > 35 – We’re already there 10-Meters: F 2 when the smoothed sunspot number > 50 – We’re right on the border for consistent worldwide openings QCWA Chap 36 April 2012 K9LA

11. Four FAQs Is Cycle 24 going to have two peaks? Is Cycle 24 going to offer any 6-Meter F 2 propagation? Are sunspots disappearing? Are we headed for another Maunder Minimum? QCWA Chap 36 April 2012 K9LA

12. Two Peaks? Cycle 19, 20, and 21 didn’t show much of a second peak Cycle 22 and 23 did show a definite second peak – Cycle 23’s second peak made 6-Meter DXers very happy in the Winter of 2001 QCWA Chap 36 April 2012 K9LA Cycle 24 has a decent chance of a second peak

13. Any 6-Meter F 2 Propagation? Not very likely (extremely low probability) with the current Cycle 24 prediction If F 2 does happen, it would be most likely during the Spring, Fall, and Winter of 2013 To reiterate, Sporadic E should still be there – Late morning and early evening in the Summer – Early evening in December QCWA Chap 36 April 2012 K9LA

14. Are Sunspots Disappearing? W. Livingston and M. Penn measured the maximum strength of magnetic fields of sunspots Strength has been declining since 1992 Need about 1500 gauss for sunspots to be visible Extrapolating their data says sunspots will disappear by 2015 2012 update – declining trend continues thru 2011 QCWA Chap 36 April 2012 K9LA Remember that sunspots are a proxy for the true ionizing radiation (EUV), which still appears to be alive and well

15. Another Maunder Minimum? Maunder Minimum was a lack of sunspots from 1645-1715 Cycles -11, -10, and -9 showed a smooth decrease in group sunspot number leading up to the Maunder Minimum – 125, 40, 20 It’s generally agreed that the Sun is “slowing down” Cycles 22, 23, and 24 exhibit a smooth decrease, too – 158, 121, around 60 to 90 Where Cycle 24 ends up and the solar minimum between Cycle 24 and 25 will be interesting, and may suggest where we’re headed QCWA Chap 36 April 2012 K9LA

16. Summary Cycle 24 maximum expected in early or mid 2013 Cycle 24 expected to be below average 15-Meters, 12-Meters, and 10-Meters are good now, so take advantage of them Have fun! QCWA Chap 36 April 2012 K9LA