Solar Surprise: Big Sunspot Peak To Come?
Earth’s sun is full of unexpected surprises. Solar Cycle 24′s story has more plot twists than a daytime soap opera.
Solar sunspot and magnetic flux activity way up in recent months
Five months ago solar sunspot activity had plummeted to just 37 spots at the midpoint of solar max. Solar flux was nil. Cycle 24 appeared to be on its death bed. Things since have dramatically changed.
For the last four consecutive months the sunspot number has been over twice as much. The Royal Observatory of Belgium reported January’s sunspot number at 82.
More significant, according to the latest ISES progression report, the sun’s monthly averaged radio flux for January hit its highest level of the current solar cycle – nearly 160 sfu. Sfu means solar flux unit.
The sun has roared back to life in the second half of this cycle. Most of that activity is in the sun’s southern hemisphere – 60.8 spots south vs. 21.2 north last month.
Sun’s Second Sunspot Peak May Exceed First!
The turnabout in solar activity is so great that the latest forecasts say the sun’s second sunspot maximum will be higher than the first one. The first sunspot peak was 66.9 in February of 2012. The second one may be around 70. Should that happen it will reverse the trend over the last six solar cycles where the second peaks were weaker than the first.
The official peak in sunspot activity comes from a weighted average sunspot number calculated over a 13-month period. It includes six months before and six months after the calculated value. It is called the “smoothed” sunspot number. It’s always six months behind the current completed month.
The most current smoothed sunspot number is 65.5 for July of 2013, six months ago. Current forecasts say it’ll hit 70 before it’s done.
Should it hit 70 it will further vindicate a remarkable trailblazing paper written back in 2004 by solar physicists Leif Svalgaard, Edward W. Cliver and Yohsuke Kamide who went against conventional wisdom and predicted Cycle 24′s maximum at an exceptionally low 75 ±8. As late as 2007 most everyone else predicted a strong peak around 140.
Solar flux is an important monitored measure of solar energy output at 2800 MHz (10.7 cm wavelength). Ham radio operators like it because high flux improves world-wide ham radio communications after staying above 150 sfu for several days.
The sun’s radio flux is directly related to solar sunspot activity. It is highest at solar maximum and lowest at solar minimum. It ranges from about 50 sfu to 300 sfu. Most solar energy output at 10.7 centimeters comes from the bright areas of high magnetic field concentration surrounding sunspots. The bright areas are called plage.
Generally speaking, ham radio operators are happiest during sunspot maximum because their signal bounce off the ionosphere is at its best. Then they can easily talk with all their friends in Australia.
Solar flux last month averaged 160 sfu. The last time it got that high was between 1999 and 2002 during Cycle 23.
Cycle 24 Still Exceptionally Weak
Current solar cycle may be closer to Dalton Minimum than to Cycle 14
The current sunspot cycle – Cycle 24 – is often compared to weak Cycle 14 back in 1907. It is about the same height and shaping up to have multiple peaks like Cycle 14.