Guest post by David Archibald
With respect to the month of minimum, it is very likely that Solar Cycle 24 has started simply because Solar Cycle 23 has run out. Most solar cycles stop producing spots at about nineteen years after solar maximum of the previous cycle. Solar Cycle 23 had its genesis with the magnetic reversal at the Solar Cycle 22 maximum. As the graph above shows, Solar Cycle 23 is now 19 years old. Only 9% of the named solar cycles produced spots after this.
The graph also shows the position of Solar Cycle 24 relative to its month of genesis. Solar Cycle 24 is now the second latest of the 24 named solar cycles. January is 105 months after the Solar Cycle 23 maximum. Only Solar Cycle 5, the first half of the Dalton Minimum, is later. This lateness points to Solar Cycle 24 being very weak.
This graph shows the initial ramp ups of six solar cycles that were preceded by a vey low minimum. The ultimate trajectory of Solar Cycle 24 should be apparent by late 2009. If Solar Cycle 24 is going to be as weak as expected, the monthly sunspot number should remain under 10 by the end of 2009.
TonyS (05:13:34) :
Now you have 1232 points smoothed. It has the same information content as the 308 points, but you can localize the peaks better. You can of course try other upsampling ratios (1to8 or 1to16)…
Since I do have monthly data 1749-2008, I don’t need to do upsampling. To minimize leakage, I go from 1755 to 2008 where both values are close to zero, so no artificial jump. I also do the smoothed SSN [blue curve] so have to stop at end of 2007. Here http://www.leif.org/research/FFT-SSN-Monthly-1755-2007.png
is the FFT [raw data: pink curve]. I is hard to get a better resolution because of the high autocorrelation and also because the solar really isn’t periodic so there is power in quite a band around 11 years.
There is only so much we can extract from the sunspot record [it is simply not long enough] and people have been trying an trying for decades. Not much has come of that, except that there seems to be an approximate 11-yr period with an 80-110 yr modulation.
it is simply not long enough
I guess we have to wait another couple hundred years… 🙂
This kind of “mystery” is what makes science so fascinating – it would be quite dull if everything was already “settled”.
And I see that I too make the mistake of thinking “if we only have enough data and look hard enough at it, we can solve all the mysteries”.
I recall reading an article that stated that a prolonged solar minimum would result in a steep ramp up to an extreme solar max. Nasa’s prediction in the last year for a strong cycle 24 would agree with that assessment.
Further, the Mayan civilization had not one, but two predictive dates for our present time – December 23, 2011 and December 23, 2012 – these dates match the projected max for cycle 24.
We are not in Dalton’s minimum anymore.
Matt Maddox
Astrosymm.com
Leif,
Is table 3 here true or not?
http://personal.inet.fi/tiede/tilmari/sunspots.html
lgl (10:48:45) :
Is table 3 here true or not?
It is typical for the pseudo-scientific approach: uses cherry picking, uses a non-standard [the ‘lone genius’ syndrome] technique, is teleological [picking what fits]. I’ll say it is junk. Is junk true or not? junk is just junk.
Leif,
Ok, then this must be junk too: http://www.ngdc.noaa.gov/stp/SOLAR/ftpsunspotnumber.html
1/3 of the cycles after 1750 between 10 and 10.6 years.
lgl (14:44:09) :
then this must be junk too: […]
1/3 of the cycles after 1750 between 10 and 10.6 years.
If you say so.
Leif Svalgaard (19:14:07) :
lgl (14:44:09) :
“then this must be junk too: […]”
If you say so.
On of the typical pseudo-science signs is the reliance on measures that have little physical meaning. The cycle length from minimum to minimum is such a quantity. A cycle begins a year or two before the ‘minimum’ and extends a year or two after the ‘minimum’. If the two cycles on either side of a ‘minimum’ are of different sizes, the ‘minimum’ will shift towards the weaker cycle making it determination even less meaningful. If the assumption is that some external agent is ‘making spots’, then a more meaningful measure of the length of the cycle is from maximum to maximum. Here are the maxima and lengths determined from the smoothed sunspot number:
1750.292 11.167 [= 1761.459 – 1750.292]
1761.459 8.252
1769.711 8.665
1778.376 9.753
1788.129 16.996
1805.125 11.250
1816.375 13.500
1829.875 7.332
1837.207 10.919
1848.126 12.000
1860.126 10.500
1870.626 13.353
1883.979 10.066
1894.045 12.077
1906.122 11.502
1917.624 10.663
1928.287 9.000
1937.287 10.083
1947.37 10.834
1958.204 10.669
1968.873 11.083
1979.956 9.583
1989.539 10.748
2000.287 12.713
2013.000
For cycle 24 I have simply guessed that maximum will be in 2013 [considering the slow start of SC24]. You can play around yourself with other guesses.
A histogram of cycle lengths so determined is here:
http://www.leif.org/research/Histogram%20Solar%20Cycle%20Lengths%201749-2013.png
The bin size was 1/2 year and the points are plotted at the bin center. A larger bin does not provide enough time resolution and a smaller bin makes the count too small to be significant. The error on a count is about the square root of its value.
The mean value of the length is 10.95 years with a standard error of the mean of 0.40 year. The median value is 10.79 years. The pink curve is a 3-point running average.
Leif
“It is typical for the pseudo-scientific approach: uses cherry picking”
lgl (05:07:11) :
“It is typical for the pseudo-scientific approach: uses cherry picking”
You got it! By golly, you got it!