Friday 30 August 2013

Are we past sunspot maximum?

Just two days ago I published a podcast that looked at current solar activity and suggested that we are heading for a double-peaked solar maximum.

Two days later Tad Cook K7RA posted this for the ARRL:


Much talk lately has centered around a possible dual peak in the current solar cycle. This would follow a pattern established in recent solar cycles. If this is so, the first peak probably occurred in the Fall of 2011. Now it appears that perhaps the second peak was in Spring 2013.

We are just a day away from the end of the month, so we won't see the actual averages until next week, but we can get a pretty close reading knowing the actual numbers for 29 of the 31 days in August.

The average daily sunspot number for the first 29 days of August was 92.2. This is above the levels for June and July, 80.2 and 86.2, but lower than April and May. This also pegs the 3-month average of daily sunspot numbers (centered on July) around 86.1, based on data from 90 of the 92 days in that period. This is above all of the three-month moving averages centered on September 2012 through March 2013, but lower than the previous three periods centered on April and May (106.4) and 97.5 for June.


While working out when solar maximum is has always been an historical activity - you don't know you are there until some months later - this may not bode well for this Autumn. So start praying to the Sun Gods for more sunspots as an SFI of 100 is nothing to get too excited about.

But as I said in the podcast, conditions will improve naturally as we head towards late September due to a change in the ionosphere's molecular/atomic ratio (and therefore recombination rate) due to seasonal changes anyway. If you are looking for decent trans-Atlantic HF propagation it will be coming along soon. But we may have already seen the best of the decent 10m worldwide propagation - at least for another 10 years or so. Ho hum!

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