Wednesday, February 10, 2016

Solar Cycle News Update - Just Can't Hide the Decline

In keeping with my every six months (more or less) update to the solar cycle progression, the latest smoothed sunspot number for the last six months.
You can see the smoothed average (blue line) is about 70% of the predicted number (red line to the right).  You can also see a decrease in the variability; the spread of the dots above and below the smoothed average.  The sun has been mostly quiet. 

Last August, I also ran the planetary A index value; a measure of geomagnetic activity, so let me refresh this.
You can see that the geomagnetic activity has continued increasing over the last six months.  To update what I said last time, I can't say I understand that increase, but the "tribal knowledge" in amateur radio circles is that geomagnetic disturbances tend to be more common in the declining years of a sunspot cycle.  The previous cycle (cycle 23) peaked at the end of 2002; and storming increased until mid '2004 (that peak at the end of '04 was the largest solar flare observed in the satellite era).  The current Ap levels (Planetary A-Index) are higher than any time since early '05."   Let me add that I've taken advantage of my increased free time in the last month to try to make contact with some rather exotic ham radio locations, and I've noticed the effects of these geomagnetic disturbances.

And to quote myself even more:
As I've posted before, this is the weakest solar cycle in 100 years, which means no living solar scientist has seen a cycle this weak, and our records of what the sun was doing back then are more sparse than what's available now.  Since no living scientist has seen a cycle this weak, expect all predictions to be even less accurate than usual.
My interest in solar activity grew out of the shortwave radio listening hobby I started when I was about 13 years old.  That was in the cycle right after the strongest one on record, the peak from the late 50s.  Solar activity acts to increase the density of the ionosphere, which raises the frequency at which radio waves are bent back to Earth.  Following the highest frequency that will propagate between two points, the Maximum Usable Frequency or MUF, is generally the way to hear (or talk with) the most distant points with the lowest loss of signal.  It's only in the last 20 years or so has it seemed that the solar cycle might affect things like our food supply, and life in general.


  1. Yeah, this cycle was a real bust.

    I always get quite a chuckle out of the Ham "experts" out there who claim every upcoming cycle will be "BIGGER Than Cycle 19!!!!!" using various "prediction" methods like the "odd-even year method", and other arcane chicken-bone throwing techniques.

    Makes me wonder if I should get that new radio I've had my eye on or not.......

  2. Looking at the "Big Picture", shouldn't the Solar Cycles, over all, be subject to the Second Law of Thermodynamics? We can only "see" a very small fraction of the total, but still ...

    1. I'm sure the sun is subject to the second law; nothing has been found exempt from it, yet. But that's a really big system (as you say), and I'm not sure I'd know how to spot it.

      The sun burns out eventually, right? At that point, entropy conquers all. I don't think any significant run down in energy has happened over all of human history.