[HCARC] OOPS Wrong Receiving Antenna Link

[Kerry Sandstrom]

Gary,

Yes the sun is cyclical, however, the cycles aren't exactly regular. 
Waldmeier, who was associated with the observatory at Zurich, published some 
data in 1961 on the solar cycles ( 1-19) up to that date.  The data included 
the mean and extreme values for several parameters.

                            parameter 
Mean                    Extremes

            Period between maxima (years) 
10.9                    7.3 - 17.1

            Period between minima (years) 
11.1                    9.0 - 13.6

            Time from min to max (years) 
4.5                     2.6 - 6.9

            Time from max to min (years) 
6.5                    4.0 - 10.2

            Maximum sunspot number (monthly mean) 
108.2                48.7 - 201.3

            Minimum sunspot number (monthly mean) 
5.1                     0 - 11.2

As you can see, the numbers are all over the place.  Yes, the sun is 
cyclical, but the cycles are far from regular.  Some cycles have had two 
distinct peaks while other cycles have had relative maxima 2 or 3 years 
after the peak which are no wheres near the peak but still quite prominent. 
The daily variation in sunspot numbers are even more extreme.  As I recall 
the maximum single day sunspot number is over 300.

The sunspot number is hardly a precise measurement.  It is used primarily 
because of its very long history.  The sunspot number is calculated by 
multiplying the number of sunspot groups by 10 and adding the number of 
individual sunspots.  For example, if there were 3 sunspot groups of 1, 4, 
and 15 sunspots, the sunspot number would be 30 + 20 = 50.   Because modern 
telescopes are so much better than the early telescopes, the sunspot counts 
of modern observatories are multiplied by a number less than 1 so that 
modern sunspot numbers can be compared to the historical sunspot numbers. 
Further complications are that sometimes the sunspot groups run into each 
other and you can only tell how many groups you have by the magnetic 
configuration of the sunspots.  We do this now but it couldn't be done 
centuries ago.  During the minimum between solar cycles, there is an 
extended period when sunspots from both the old cycle and the new cycle are 
present.  The two indicator sof which cycle a group belongs to is its solar 
lattitude and its magnetic configuration.

Various people have found, through numerical analysis, several cycles 
besides the basic 22 year magnetic field/sunspot number cycle.  All these 
cycles seem to have very small amplitudes compared to the basic cycle and 
over time the length of these cycles seems to vary.  The most often quoted 
ones are a 26 month cycle and an 80 year cycle.  Any underlying physical 
cause of these cycles has been elusive.  There is a 27 day cycle which is 
fairly well established and is due to the sun rotating around its axis every 
27 days at the equator.  Other lattidues have other rotation rates, the sun 
is not a rigid body.  Since sunspots are generally near the equator, the 27 
day rotation is a reasonable approximation.

So back to the Maunder minimum.  It is real.  there were 1 or 2 other 
similar periods however, it would be difficult to say that there is any real 
predictable cycle.  Could we have another long minimum like the Maunder 
minimum - yes.  Is it certain to occur - who knows, I certainly don't.  Are 
we going to have another solar cycle minimum in the next few years - 
absolutely.  Would I worry about how I'm going to operate through another 
Maunder minimum - No.  Would I make plans on how I'm going to operate 
through the next solar cycle minimum - Absolutely.

Just my opinions, of course, but based on studies of real scientific 
literature.

Kerry