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Sunspot Minimum Finally

By Joe D'Aleo
Monday, June 15, 2009

We have been reporting on the unusually quiet sun and ultralong solar cycle over the last year.


The sun has become more active in early June with cycles 24 spots in middle latitudes. See sunspot group number 11019 for group of red spots. This is slightly diminished since yesterday. The dark green areas are coronal holes out of which the solar wind escapes at higher velocity.

Peter Lawrence has a close up view of that sunspot posted on

There is a loop of the sunspots develop and rotate around the solar disk the last few days here.

This has been an unusual cycle as we have been reporting. In 2003 and as late as 2006, NASA was expecting a start to the new cycle in December 2006 and a big cycle 24 peaking in 2010 or 2011. In subsequent releases by NASA, the new cycle was pushed back and estimates for the amplitude decreased. See the history of the NASA and NCAR debacle on the solar forecasts here.


On Sept. 23, 2008, in a briefing at NASA headquarters, solar physicists announced that the solar wind is losing power. "The average pressure of the solar wind has dropped more than 20% since the mid-1990s," says Dave McComas of the Southwest Research Institute in San Antonio, Texas. "This is the weakest it's been since we began monitoring solar wind almost 50 years ago."


Here we are in middle 2009, and we are just now seeing the increase in cycle 2004 activity.

This activity came late enough in the month of May, to keep the monthly number for May below the value of 14 months ago of 3.2 which it is replacing in the 13 month running mean. That means the solar cycle minimum can’t be earlier than November 2008, making it at least a 12.5 year long cycle 23. This about two years after the early estimates of the solar minimum.

The value needs to fall below 3.4 in June to move the minimum to December. That is still possible if the sunspot group continues to decay as most have done as they crossed the disk in recent months. If it stays below that value, we will likely see the solar minimum in December, 2008 as 14 months before that the sun was very quiet with just a sunspot number of 0.5. If not, the minimum will be November. It is my guess that November will win the prize.  


We added 22 more sunspotless days to the total for this cycle transition which as of June 1 had now reached an amazing 614 days. We are likely to add additional days and add 2009 to 2007 and 2008 as recent years in the top ten since 1900. Only the early 1900s had a similar 3 year stretch of high sunspot days (1911, 1912, and 1913).

It also marks the longest cycle in 150 years, tying the one that peaked in 1848. You have to go back to the Dalton minimum in 1816 to find a longer cycle 12.7 years.

You can see in 3 of the 5 most recent cycles, the sun had rebounded significantly by years 12 and 13 well into the next cycle.

Theodore Landscheidt in New Ice Age Instead of Global Warming warned the decline could continue in solar activity until a Maunder Minimum like level was reached about 2030.

The Russians appear to agree. Khabibullo Abdusamatov of the Russian Academy of Science said he and his colleagues had concluded that a period of global cooling similar to one seen in the late 17th century - when canals froze in the Netherlands and people had to leave their dwellings in Greenland - could start in 2012-2015 and reach its peak in 2055-2060.

The late Rhodes Fairbridge of Columbia University had found with the help of NASA and the JPL, every 179 years or so, the sun embarks on a new cycle of orbits. One of the cooler periods in recent centuries was the Little Ice Age of the 17th century, when the Thames River in London froze over each winter. The next cool period, if the pattern holds, began in 1996, with the effects to be felt starting in 2010. Some predict three decades of severe cold. See recent story on Rhodes’s findings also here.

Clilverd et al (2006) in a paper “Predicting Solar Cycle 24 and Beyond” found by using an harmonic analysis of the multiple cycle frequencies of solar cycles in a model that correctly has caught the activity the past 250 years with a sunspot number standard deviation of 34. Their analysis suggest cycles 24 and 25 will be the lowest (quietest and thus coolest) in nearly 200 years. The two cycles should be like those of the Dalton Minimum.

That was the Dicken’s era, a period with snow frequently in London, much as we saw last winter.

David Archibald in Energy and the Environment and in the paper The Past and Future of Climate this last year agreed with this projection.


The temperatures with such a decline projected by Archibald are significant.



That decline has already begun even as CO2 has continued to rise.



Needless to say much will be learned the next 5 years if the solar cycle decline with cooling temperatures continues. Read more on the possible solar factors here. See forecasting methods here.


Also see this Daily Tech article on NASA research confirming solar cycle effects on climate.



Past studies have shown that sunspot numbers correspond to warming or cooling trends. The twentieth century has featured heightened activity, indicating a warming trend.  (Source: Wikimedia Commons)



Solar activity has shown a major spike in the twentieth century, corresponding to global warming. This cyclic variation was acknowledged by a recent NASA study, which reviewed a great deal of past climate data.  (Source: Wikimedia Commons)


Report indicates solar cycle has been impacting Earth since the Industrial Revolution

Some researchers believe that the solar cycle influences global climate changes.  They attribute recent warming trends to cyclic variation.  Skeptics, though, argue that there's little hard evidence of a solar hand in recent climate changes.

Now, a
new research report from a surprising source may help to lay this skepticism to rest.  A study from NASA’s Goddard Space Flight Center in Greenbelt, Maryland looking at climate data over the past century has concluded that solar variation has made a significant impact on the Earth's climate.  The report concludes that evidence for climate changes based on solar radiation can be traced back as far as the Industrial Revolution.

Past research has shown that the sun goes through eleven year cycles.  At the cycle's peak,
solar activity occurring near sunspots is particularly intense, basking the Earth in solar heat.  According to Robert Cahalan, a climatologist at the Goddard Space Flight Center, "Right now, we are in between major ice ages, in a period that has been called the Holocene."

Thomas Woods, solar scientist at the University of Colorado in Boulder concludes, "The fluctuations in the solar cycle impacts Earth's global temperature by about 0.1 degree Celsius, slightly hotter during solar maximum and cooler during solar minimum.  The sun is currently at its minimum, and the next solar maximum is expected in 2012."

According to the study, during periods of solar quiet, 1,361 watts per square meter of solar energy reaches Earth's outermost atmosphere.  Periods of more intense activity brought 1.3 watts per square meter (0.1 percent) more energy.

While the NASA study acknowledged the sun's influence on warming and cooling patterns, it then went badly off the tracks.  Ignoring its own evidence, it returned to an argument that man had replaced the sun as the cause current warming patterns.  Like many studies, this conclusion was based less on hard data and more on questionable correlations and inaccurate modeling techniques.

The inconvertible fact, here is that even NASA's own study acknowledges that solar variation has caused
climate change in the past.  And even the study's members, mostly ardent supports of AGW theory, acknowledge that the sun may play a significant role in future climate changes.


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