The sun is currently active but geomagnetic conditions are quiet. There are 5 sunspots (all in one area) on the side of the sun we can see and the 10.7 cm radio flux density is 114. Despite my son's explanation, I still have no real idea what flux density is. We are approaching the peak of solar activity in the current cycle, number 24. At one time during the very
long solar minimum after cycle 23, many scientists were predicting
that the peak of cycle 24's activity would be above that of cycle 23, in other words, a medium strong cycle
. They have had to back track from that prediction to where their prediction is now at roughly half the activity of cycle 23. And cycle 24 is under-performing even that revised prediction. To match the average peaks of the last 7 cycles, going back to the late 30s, early 40s, there should be 10 to 12 sunspots each day, and the radio flux density should be around 220 (it never gets above 270). It is a much less active sun than the past 80 year "normal." Indeed, this cycle has been the weakest since the weak cycle 14 between 1900 and 1910, and the third weakest since they've began numbering the cycles in the 1750s.
The relative quiet cycle of sunspots is matched by the ISES Solar cycle Ap progression (I have no idea what that is) which hasn't gone above 15 since around October 2005. Before that it was generally at
15, usually peaking in the 20s and sometimes peaking as high as 35. It's as if a "switch" inside the sun was shut off and the sun powered down to a new, much lower "normal."
Worst of all (for those who fear an end of the current interglacial), the Umbral Magnetic field continues to decline from 2600 Gauss in 1998 to about 2100 now. Scientists say that all sunspot activity ends at 1400 Gauss which we'll reach, if the downward progression stays as steady as it has, around 2025. Historically, years of sunspot absence are followed here on Earth by very cold weather, sometimes lasting centuries. That ain't so good.
There are much greater threats, all natural, to our current benign climate than a one ten thousandth increase of a trace gas in our very stable atmosphere.
Some sun watchers are suggesting that, rather than 2013 being the peak of the cycle, as the much reduced prediction at NOAA suggests (red line on the graph), the peak already took place. Maybe, but the last cycle had a double peak.
It could happen again. Still, the cycle is less than half of the last one, so far.
Labels: Yearly Report on the Sun