Sunspots reaching 1,000-year high

BBC News ^ | Tuesday, 6 July, 2004 | Dr David Whitehouse

[George W. Bush]

Sunspots reaching 1,000-year high

By Dr David Whitehouse
BBC News Online science editor

Sunspots are plentiful nowadays

A new analysis shows that the Sun is more active now than it has been at anytime in the previous 1,000 years.

Scientists based at the Institute for Astronomy in Zurich used ice cores from Greenland to construct a picture of our star's activity in the past.

They say that over the last century the number of sunspots rose at the same time that the Earth's climate became steadily warmer.

This trend is being amplified by gases from fossil fuel burning, they argue.

'Little Ice Age'

Sunspots have been monitored on the Sun since 1610, shortly after the invention of the telescope. They provide the longest-running direct measurement of our star's activity.

The variation in sunspot numbers has revealed the Sun's 11-year cycle of activity as well as other, longer-term changes.

In particular, it has been noted that between about 1645 and 1715, few sunspots were seen on the Sun's surface.

This period is called the Maunder Minimum after the English astronomer who studied it.

Ice cores record climate trends back beyond human measurements

It coincided with a spell of prolonged cold weather often referred to as the "Little Ice Age". Solar scientists strongly suspect there is a link between the two events - but the exact mechanism remains elusive.

Over the past few thousand years there is evidence of earlier Maunder-like coolings in the Earth's climate - indicated by tree-ring measurements that show slow growth due to prolonged cold.

In an attempt to determine what happened to sunspots during these other cold periods, Dr Sami Solanki and colleagues have looked at concentrations of a form, or isotope, of beryllium in ice cores from Greenland.

The isotope is created by cosmic rays - high-energy particles from the depths of the galaxy.

The flux of cosmic rays reaching the Earth's surface is modulated by the strength of the solar wind, the charged particles that stream away from the Sun's surface.

And since the strength of the solar wind varies over the sunspot cycle, the amount of beryllium in the ice at a time in the past can therefore be used to infer the state of the Sun and, roughly, the number of sunspots.

Latest warming

Dr Solanki is presenting a paper on the reconstruction of past solar activity at Cool Stars, Stellar Systems And The Sun, a conference in Hamburg, Germany.

He says that the reconstruction shows the Maunder Minimum and the other minima that are known in the past thousand years.

But the most striking feature, he says, is that looking at the past 1,150 years the Sun has never been as active as it has been during the past 60 years.

Over the past few hundred years, there has been a steady increase in the numbers of sunspots, a trend that has accelerated in the past century, just at the time when the Earth has been getting warmer.

The data suggests that changing solar activity is influencing in some way the global climate causing the world to get warmer.

Over the past 20 years, however, the number of sunspots has remained roughly constant, yet the average temperature of the Earth has continued to increase.

This is put down to a human-produced greenhouse effect caused by the combustion of fossil fuels.

This latest analysis shows that the Sun has had a considerable indirect influence on the global climate in the past, causing the Earth to warm or chill, and that mankind is amplifying the Sun's latest attempt to warm the Earth.

[Nowhere Man]

BTw, I have a couple of Radio Handbooks, the 1st edition from 1935 and the 14th or 15th editionsfrom 1957/59. I think in both, I know the latter, there is a claim that there could be a larger 22 year sunspot cycle too. About activity being the highest from the 1950’s onward, I do remember reading about TV Dxing back in the 1950’s where people in the Eastern US pulled in stations as far away as Cuba and Hawaii. In the late 1930’s, when the sun got active, some TV researchers in New York managed to watch BBC 405 line television in the 40 - 45 Mc band from across the Atlantic.

[Nowhere Man]

Sorry about the triple post, how in the heck that happened, I dunno. B-P I’ll just blame sunspots. B-D

[justa-hairyape]

My guess is the Sun and its interaction with our planet is going to turn out to much more complex then some of us Apes really want it to be. The known cycles are: 27 day; 11 year; 22 year; 80 year; 180 year; and longer. We typically measure Watts/square meter and count sunspots, but that is going to turn out to be only a very small part of the overall picture. Besides sunspot cycle amplitude there is also sunspot cycle length, solar equatorial rotational rate, penumbral spot fractions and the sunspot cycle decay rate. Besides normal average irradiance there are also energetic flares that can increase UV radiation by 16 %. That UV is absorbed by Ozone in the stratosphere and the heat has been shown to propagate down and affect the circulation in the Troposphere. Solar radio flux has also been shown to vary quite dramatically. Solar winds and geomagnetic storm strengths have been shown to cause ionization warming in the polar auroral zones. Solar Wind output has been shown to affect the number of Galactic Cosmic Rays that reach Earth. In addition to all these factors, the sun can be very unpredictable. Just examine the incredibly intense Radio Flux and Huge Sunspot Areas that occurred from October 23 to November 3rd of 2003. That was during a falling sunspot cycle that was only at half amplitude. Additionally, disturbances that occur in the equatorial region of the sun may also affect our planet much greater due to the orbital plane. NASA itself readily admits that we are just getting started with respect to monitoring and fully understanding Solar Weather. So the factors I listed here are just what we will find in the introductory section of the Solar Weather textbook.

[justa-hairyape]

FYI - Concerning that October 23 to November 3rd of 2003 time frame. There were two very large flares that were sent our way. On October 28th 2003 an X17.2 was the 4th largest flare we have ever seen. Image courtesy of SolarCycle24.com.

Then on October 29th 2003 an X10 flare was the 20th largest flare we have ever seen. Image courtesy of SolarCycle24.com.

Then on November 4th 2003 the largest solar flare we have ever seen occurred and it was an incredible X28+. Lucky for us the Earth and Sun had moved enough by then that the super flare was not aimed at our planet.

SolarCycle24.com Movie

Also forgot to note the Coronal Mass Ejections (CME) that affect Earths magnetosphere. They are so powerful they can cause damage to satellites and electrical transmission lines. Trillions of watts of power are created and directed back to the Earth's upper atmosphere when these CME's hit our magnetopshere.

[cogitator]

Here's the abstract for the paper that provided that data:

Evolution of the Sun's spectral irradiance since the Maunder Minimum. Geophysical Research Letters, Volume 27, Issue 16, p. 2425-2428.

"Because of the dependence of the Sun's irradiance on solar activity, reductions from contemporary levels are expected during the seventeenth century Maunder Minimum. New reconstructions of spectral irradiance are developed since 1600 with absolute scales traceable to space-based observations. The long-term variations track the envelope of group sunspot numbers and have amplitudes consistent with the range of Ca II brightness in Sun-like stars. Estimated increases since 1675 are 0.7%, 0.2% and 0.07% in broad ultraviolet, visible/near infrared and infrared spectral bands, with a total irradiance increase of 0.2%."

That paper is cited in this recent overview:

Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties (2005)

and this section is probably relevant ;-)

Solar Forcing

[wolfcreek]

“When massive power outages occur, more babies are born nine months later than would be otherwise.”

Not in Texas! When that AC goes out, so does the passion.

[gleeaikin]

The decline of Mayan civiliation may indeed have been influence by solar induced global warming. One effect could have been an increase in severe droughts. This seems to be one of the causes of the Darfur crisis. Also in the last global warmest period in historical times, sea levels were 5 to 8 feet higher than they are today. Whether global warming is natural and man caused, we better start thinking about sea levels pretty darn quick. New Orleans was only a wake up call.

[cinives]

Would that be in the summer only, or even in January ? :)

Gee, Texans must be getting to be like blue state weenies - the state must have been populated somehow, long before A/C.

[tje]

Great list of quotes.. thanks...

[ChildOfThe60s]

Same kooks, different tune.

[Former Proud Canadian]

Great quotes GW. Worth a bump.

[ChessExpert]

Thanks for your excellent post. I wasn’t satisfied with references to the 11 year solar cycle as though that said it all. I knew it had to be more complicated.

Looking at graphs of annual sunspots, I could make out a cycle but not a regular 11 year cycle.

Even with improved understanding, I suspect we will be left with a random, unexplained component to solar behavior.

[wolfcreek]

“Would that be in the summer only”

That would be 8 months out of the year.

I would like to personally invite you to work outside with me on a 100 degree day and see if you want to have sex (not with me) in a house with no A/C.

Maybe under a cool shower. LOL!

[justa-hairyape]

Even with improved understanding, I suspect we will be left with a random, unexplained component to solar behavior.

The underlying sunspot frequency gives an approximation to the average output and unfortunately most people just graph this out with a moving average curve. I am looking at a chart I made from reported actual values of Sunspot Area (10E-6) and Radio Flux (10.7 cm) from Jan 1st 1994 to present. According to this chart the peak sunspot area and peak Radio Flux occurred during late Oct-Nov 2003, which was late in the cycle and a couple of years after the cycle maximum. And since there were some very large flares associated with this short period, the affects could have been significant. This may be why the warming lasted longer then usual for this cycle.

The affects from this 2003 short term super active period should have been assimilated by now. We should now remain cool through 2007, possible stop cooling in 2008 and might start warming again in 2009 or 2010. It all depends on the average sunspot peak of the next cycle and whether we have any of those short term super active periods. Scientists are predicted Cycle 24 should be stronger then Cycle 24 and Cycle 25 will be very weak.

[justa-hairyape]

oops. Should read ‘Cycle 24 should be stronger then Cycle 23’

[Robert A Cook PE]

Interesting “coincidence” that the north pole magnetic position and intensity are rapidly decreasing and moving from their previous positions at the south coast of Hudson Bay.

Now, over the past twenty years, it has very, very quickly begun moving to Siberia while becoming noticeably less distinct.

Most of the previous magnetic reversals have occurred at the same time as a global ice age. (I think the number is 12 of 15 magnetic reversal match ice ages intervals.)

[Robert A Cook PE]

Well, the “end” of the Mayan calender in 2012 with the second Venus transition of the sun will match the max point of this solar cycle.

[justa-hairyape]

Should clarify, if you only look at the moving averages, short term significant factors get lost. That has always been my major gripe with modern science. Occam’s Razor sometimes minimizes perception and observation. Sometimes the details are as important as the generalities. This is probably especially true with Solar Flares that are aimed toward us and sunspots that are located near the equator. What we need to do is determine the most significant factors and then watch the sun every minute of every day with our new instruments. General trends can then be predicted and modified by short term events. Different solar effects will also have different delay factors concerning their affects on ground temperatures. Visible light variances may have short term ground temp affects and delayed sea temps affects. UV variances may have long term ground temp affects. It will probably turn out to be somewhat complicated, but at least it is not rocket science :>.

[justa-hairyape]

Most of the previous magnetic reversals have occurred at the same time as a global ice age. (I think the number is 12 of 15 magnetic reversal match ice ages intervals.)

NASA scientists using models are predicting that Solar Cycle 24 will have a maximum amplitude slightly stronger then Cycle 23. It will be interesting to see if these predictions are true. They could be wrong. The same scientists using the same models (I believe) are also predicting that Cycle 25 will be very weak. Seems odd that one of the weakest cycles ever will follow a stronger one. But hey, I am not a scientist. Moved out of the dorm and into a party house on my third year of college. Had fun at least. Been self taught since then.

[InterceptPoint]

Are those darn sunspots acting up again?

I really think that sunspots are envious of carbon dioxide who has been getting all of that global warming attention lately and they just wanted to do something to make people notice them. Not to worry.Those pesky sunspots will all go away in a few years, at least most of them, and then we can get back to worrying about CO2 again.