Solar Science ||

Subscribe (?) Subscribe to RSS
A blog of solar physics

A very good question

Published on May 6th, 2008 in 8 Comments »

OK, so I’ve recently bemoaned my fortune in actually seeing an SC24 spot “live”. But there’s a much more serious question which Anthony Watts has brought up:

Galileo, Wolf, and other solar observers of the past would likely never have seen it. So with these Tiny Tims coming and going so quickly, that begs the question; was the Maunder Minimum, Dalton Minimum and other minimums not simply a period of Tiny Tim sunspots that nobody could detect with the observing equipment of the time?

THAT is a very good question.

History of sunspot number observations showing the recent elevated activity.

Above is the record of the Solar Cycle right back to the Maunder Minimum. As you can see Galileo reported sunspots just before the Maunder Minimum, which was fortunate because with the instrumentation available at the time, he would not have seen the “Tiny Tims” similar to the current SC24 ones.

I hope this isn’t what we’re seeing. If the Earth’s climate is dominated by variations in Solar luminosity and magnetic field strength as is believed by some, then that would mean cooling.

And that would be a global disaster as deserts expand, storms increase, glaciers expand and wipe out towns and villages in places like Switzerland and Nepal, a shorter growing season with more variability in precipitation, an increase in the number of droughts and failed harvests leading to mass starvation in certain regions.

I hope its just a hiccup in global warming, because there’s very little to be scared of in a warming climate.

Before the current scare began, climatologists talked of warm periods as “Optimums” or “Optima”, a time of plenty and societal growth and prosperity. With the advent of political supplication to climate models and the pronouncements of some climate modellers, we have been taught to fear warming and try to reverse it as wholly undesirable even at the expense of every modern device that keeps us from being victims of climate change, howsoever caused.

I really hope for global warming. At the moment, I’m pessimistic about whether it will continue.

SC24: I must be cursed

Published on May 4th, 2008 in 9 Comments »

Either SC24 is the weakest ever solar cycle in a long time or I’m cursed. I look on Anthony Watts‘ excellent weblog and see that someone has sighted an SC24 spot in the Southern Hemisphere

And here’s the magnetogram showing that it is indeed an SC24 phenomenon:

If you care to look at the last SC24 spot to appear in the Northern Hemisphere, then this does appear to be an SC24 spot, (the magnetic polarities being reversed between the hemispheres).

So I snap into action, going to SolarCycle24.com and…

latest_mdi_igram040508section.GIF

…is that it? Or is it a dead pixel in the camera? Let’s check the magnetogram:

missedsc24spot040508section.GIF

…and its gone!

Another SC24 “Tiny Tim” and I missed it.

Clearly spotting sunspots is more difficult than I thought. There cannot be more than a few hours between Anthony’s post and mine, and yet the SC24 spot and magnetic signature had both disappeared.

And on a sad note, it appears not to have been given a number by NASA. Maybe the person responsible went for coffee at just the wrong time.

For some, the waiting is becoming unbearable…

Published on April 25th, 2008 in 1 Comment »

This just in from Kevin (aka VE3EN) over at solarcycle24.com

Patience is a virtue, Kevin.

Fool me

Published on April 23rd, 2008 in No Comments »

I look on solarcycle24.com. I see a high latitude sunspot number 992.

spot992-arrow.GIF

I think “hurrah! SC24 has finally shown itself”. I check the magnetogram.

magneto-992-closeup.GIF

The black arrow points to sunspot 992 - and its an SC23 spot! Its the same polarity as the SC23 magnetic signatures further south.

The red arrow points to the reversed polarity SC24 phage left by the tiny SC24 spot left a week ago.

Fool me.

Ken Tapping: The Current Solar Minimum

Published on April 22nd, 2008 in 32 Comments »

I received this via e-mail from K7RA. The original document comes from Dr Kenneth Tapping who was quoted not long ago regarding the solar cycle being “the quietest [he’d] ever seen in 25 years”. This was taken to mean that the current solar minimum was historically unusual, and here Dr Tapping explains that this is not so.

I reproduce here the entire document (other than stylistic changes from PDF to the blog, not a word or a graph has been altered from the original):

The Current Solar Minimum

Ken Tapping, 2008-04-17

This note summarizes my current feeling about the state of solar activity and the solar activity cycle. Any conclusions currently in circulation that have been drawn by extrapolating what you see in this note should not be regarded as reflecting my views. My conclusions are in this note. The information used here is freely available and readers are strongly encouraged to get the data, look at it and draw their own conclusions.

The current solar activity is not that unusual. At this point it is completely unjustified to see current solar behaviour as an indication of any departure from its what the Sun has been doing for at least the last 300 years.

Figure 1 shows a plot of solar activity as measured by the solar radio flux monitors operated by the National Research Council of Canada.

tapping-figure1.JPG

Figure 1: Monthly averaged 10.7 cm solar radio flux solar activity index since 1947 (monthly means).

The arrow under the 1964-1977 cycle indicates the length of that cycle, which was a little longer than the others. That same arrow has been copied and put under the last cycle. The length is unchanged. It can be seen that the current solar activity cycle (now ending) has not yet exceeded the length of the 1964-77 cycle. It is also clear that the longish cycle in 1964-77 was followed by further activity cycles - normal solar behaviour. To exceed the duration of the 1964-1977 cycle, the new cycle would have to delay its start at least well into 2009.

Figure 2 shows the 1964-77 and the 1997-? cycles overlaid on the same plot. Once again we can see the last cycle has yet to last longer than the 1964-77 cycle.

tapping-figure2.JPG

Figure 2: The 1964-77 cycles compared. The current cycle (black trace) has yet to last longer than the 1964-77 cycle (red trace).

The 10.7 cm solar flux covers only about six solar activity cycles. Sunspot number data covers at least 300 years. The histogram Figure 3 shows how the durations of the cycles as seen in the sunspot data have varied since 1700. A 13-year activity cycle is not that unusual.

tapping-figure3.JPG

Figure 3: Distribution of solar cycle durations over the last 300 years. The 1964-1977 cycle, having a
duration of 13 years is unusual, but not that unusual.

CONCLUSION: AT THE MOMENT IT IS UNJUSTIFIED TO ASSUME THE SUN IS UNDERGOING A SIGNIFICANT CHANGE IN BEHAVIOUR. ON THE BASIS OF SUNSPOT NUMBER DATA, WE CANNOT ASSUME ANYTHING ODD IS HAPPENING UNLESS THE NEXT CYCLE DELAYS ITS START INTO 2009 OR 2010.

Solar Cycle 24: Do we count Tiny Tims?

Published on April 19th, 2008 in 6 Comments »

Another week of excitement as the second solar cycle 24 spot appeared…and then disappeared just as rapidly.

I can’t help feeling that with an unprecedented amount of high technology monitoring the Sun with ever higher resolution, the criteria by which a sunspot is defined has become radically weakened to such an extent that it all becomes meaningless.

On Climate Audit commenters noted that the criteria for naming hurricanes had become so weakened that practically any frontal wave in the Eastern Atlantic that persisted for more than a few hours got a name (the so-called “Tiny Tims” of the hurricane season).

So it appears to be with sunspots and Solar Cycle 24. Here is that second solar cycle 24 sunspot numbered for all to see:

mdi_sunspotsgif.jpg

Now in order to ascertain that there really is a spot there, I had to first make sure my laptop screen was really clean because it could have been hidden behind a rogue speck of dust and I could have missed it.

Can you spot it? If so, you’re better than I.

Here’s three views looking at the same spot. It may be there in the magnetogram showing the class signs of magnetic polarity reversal and there may be an associated phage (often the precursor of a sunspot) but is there a sunspot?

spotthesc24spot.jpg

Meanwhile a few days later, yet another SC23 spot comes into view.

I can’t help but feel that this is all a little desperate. SC24 continues to surprise with its general unwillingness to make an unambiguous appearance.

K7RA on solar cycle “pessimists” and “optimists”

Published on March 15th, 2008 in 4 Comments »

An interesting overview on the two competing theories within NASA on Solar Cycle 24 from amateur solar watcher Tad Cook, also known under his radio ham designation K7RA:

A new forecast is out regarding progress between Solar Cycles 23 and 24. You may recall that the committee of scientists who make a group forecast of future sunspot activity for the NOAA Space Weather Prediction Center were unable to reach a consensus last year, the group evenly split between those who think the next solar cycle will be weak and those that see a stronger solar cycle.

I will refer to the weak cycle predictors as pessimists and strong cycle forecasters as optimists. While these characterizations may not be appropriate for scientists who presumably have no preference either way, as far as Amateur Radio operators are concerned, the high cycle prediction is no doubt the optimistic choice.

The previous prediction appeared in the January 2, 2008, issue 1687 of the Preliminary Report and Forecast. Note on page 8 in the table of predicted smoothed sunspot numbers that the optimistic faction predicts a sunspot minimum of 4 centered around December 2007-April 2008. The pessimistic projection is for a smoothed sunspot number minimum of 3 from January-April 2008.

Now compare this with the prediction ten weeks later on page 9 of issue 1697 from this week. See how the pessimists are now calling for a much longer and lower solar minimum lasting over a year, from November 2007-December 2008. But according to the optimists, the solar minimum has already passed, with a smoothed sunspot number of 6 in August and September 2007 (this generally agrees with our 3-month averages of daily numbers, presented in last week’s bulletin.)

Note there is no split in the value for August 2007. This is because 6 is the known smoothed sunspot number for that month, not a prediction. A year of daily sunspot numbers is required to calculate the smoothed value, and all of the values from mid-February 2007 through mid-February 2008 (a whole year with August in the middle) are known. In fact, enough sunspot data will be known this weekend to fix the smoothed sunspot number for September of last year.

Now look at even better news for sunspot fans. See how the predictions for the peak of the next solar cycle have shifted and both factions see Cycle 24 peaking much higher than they did 10 weeks earlier.

In issue 1687, pessimists predicted a peak between May and October 2012 of only 90, but now in issue 1697, we see a much higher and earlier peak at 124 from August-December 2011, only three and a half years from now. The optimists and pessimists now agree on the timing of the peak, and optimists have upped their peak value prediction from 140 to 154 (access all recent weekly issues here.)

Of course, with only 23 cycles of data to examine, sunspot cycle prediction is still a young science. But new tools unavailable in past decades no doubt have advanced the art.

A couple of SC24 predictions

Published on March 5th, 2008 in 3 Comments »

David Archibald (as reported by Ronald Bailey at Reason magazine):

One of the more remarkable performances was by Australian entrepreneur David C. Archibald during one of the afternoon panels. Archibald is described in the conference materials as “a scientist operating in the fields of cancer research, climate science, and oil exploration.” He also appears to have business interests in some oil fields in Australia. In any case, Archibald made it very clear that he is a big believer in the idea that climate change is primarily driven by the sun. Archibald’s basic theory is that when the sun’s magnetic field strength drops there are fewer sunspots which reduce the amount of particles ejected as the solar wind. Less solar wind allows more galactic cosmic rays to enter the Earth’s atmosphere. Archibald is here relying on studies by Danish physicist Henrik Svensmark which find that cosmic rays do produce cloud condensation nuclei which then might create low level clouds that reflect more sunlight back into space thus making the Earth colder.

Archibald predicts that the next solar cycle, Cycle 24, will produce a weak magnetic field which means that more cosmic rays will enter the atmosphere to create clouds and thus cool the earth. Actually, a 2007 NASA scientific panel was evenly split on the strong/weak prediction for Cycle 24. However, manyresearchers expect that Cycle 25 may be one the weakest in centuries. Archibald ended by boldly predicting that the world will see average temperatures drop by -2.2 degrees centigrade in the coming decade. That’s more than three times the amount of warming the world has experienced over the last century. He also predicted as a consequence that the growing seasons in the United States would be shortened by a total of four weeks, dramatically reducing food production.

Piers Corbyn: astrophysicist and Earth weather predictor at Weather Action (personal communication):

…I would say that solar cycle 24 has NOT yet begun in the sense that we have not yet reached the smoothed minimum normally used to define the transition.

As far as the (Jan 3rd) NASA sighting (’claim’?) of a reverse polarity spot, I don’t suppose there is any doubt that it was seen but I do agree with your implied statement that it doesn’t amount to much.

As a rough estimate we don’t expect any (more/lasting) reverse polarity spots until maybe shortly after mid-March at the earliest.

Paste this into your blog if you wish.

It will be worth referring back to these once SC24 has established itself in whatever form it turns out to be in.

Popular Mechanics on the Solar Minimum

Published on February 7th, 2008 in 6 Comments »

Joe Pappalardo at Popular Mechanics has a fascinating article on the possible (probable?) result of an extended solar minimum such as that which we are experiencing: global cooling:

Every day, scientists hoping to see an increase in solar activity train their instruments at the sun as it crosses the sky. This is no idle academic pursuit: A lull in solar action could potentially drive the planet’s temperature down, or even prompt a mini Ice Age.

Woah! I wonder if Joe has heard about the overwhelming scientific consensus that denies such a result? Maybe I should sic James Hansen on him…

For millennia, thermonuclear forces inside the star have followed a regular rhythm, causing its magnetic field to peak and ebb, on average, every 11 years. Space weathermen are watching for telltale increases in sunspots, which would signal the start of a new cycle, predicted to have started last March and expected to peak in 2012. “When the sun’s active, it’s a little bit brighter,” explains Ken Tapping, a solar researcher and project director for Canada’s National Research Council.

So far, Tapping reports no change in the magnetic field strength, as measured by radio telescopes. On the more positive side, last month NASA reported a small, earth-sized sunspot with a magnetic field pointing in the opposite direction from those in the previous cycle; qualities that designate the spot as a signal of a new upturn in activity. At the solar maximum, scientists expect to see between 75 and 150 such sunspots per day.

Tapping oversees the operation of a 60-year-old radio telescope that he calls a “stethoscope for the sun.” Recent magnetic field readings are as low as he’s ever seen, he says, and he’s worked with the instrument for more than 25 years. If the sun remains this quiet for another a year or two, it may indicate the star has entered a downturn that, if history is any precedent, could trigger a planetary cold spell that could bring massive snowfall and severe weather to the Northern Hemisphere.

The last such solar funk corresponded with a period of bitter cold that began around 1650 and lasted, with intermittent spikes of warming, until 1715. While there were competing causes for the climatic shift—including the Black Death’s depopulation of tree-cutting Europeans and, more substantially, increased volcanic activity spewing ash into the atmosphere—the sun’s lethargy likely had something to do with it.

Of course, no mention of greenhouse gases.

Just how much influence the sun has on global temperatures has been the subject of sometimes acrimonious debate. While an upswing in solar activity may cause a warming trend, it was discounted in the mid-1990s as the sole driver of current climate change. And for anyone hoping that a solar downswing might bail us out of our current dilemma: Solar influence on climate is slight compared to the impact of man-made greenhouse gases, a National Academy of Sciences report concluded in 1995.

Ah, there it is! So what we have is a contest between global warming due to greenhouse gases, and global cooling due to solar dimming.

Its a dilemma as to what to wish for. Global cooling such as the Little Ice Age would have been a technological challenge to modern 21st Century agriculture, technology and energy resources. What’s there to worry about with global warming? Deserts like the Sahara shrinking is a bad thing to be avoided…like the Plague?

Solar Cycle 24: False Starts

Published on February 4th, 2008 in 8 Comments »

In early January 2008, NASA reported the start of Solar Cycle 24 with the sighting of a tiny reversed polarity spot. It lasted three days and then disappeared.

This was reported by Anthony Watts thus:

Solar physicists have been waiting for the appearance of a reversed-polarity sunspot to signal the start of the next solar cycle. The signal for the start of a new cycle is sighting a particular kind of sunspot. That wait is over.

And the NASA blog said:

“On January 4, 2008, a reversed-polarity sunspot appeared—and this signals the start of Solar Cycle 24,” says David Hathaway of the Marshall Space Flight Center.

Above: Images of the first sunspot of Solar Cycle 24 taken by the NASA/ESA Solar and Heliospheric Observatory (SOHO).

Solar activity waxes and wanes in 11-year cycles. Lately, we’ve been experiencing the low ebb, “very few flares, sunspots, or activity of any kind,” says Hathaway. “Solar minimum is upon us.”

But the first announcement of Solar Cycle 24 wasn’t made by NASA in January 2008 - it was actually made by Ulrich Reith on 31 July 2006, with this post:

Last night it seems to have happend, the first sunspot of solar cycle 24 appeard on the southern hemisphere of the sun.
Very close to NOAA 10902 a tiny spot which should be named 10903 appeared at S12W55.
In the SOHO MDI magnetogramms it clearly shows a reversed polarity if compared to the polarity of cycle 23. (cycle 23: black first towards the western limb and white following black / cycle 24: white in front of black)

And I show the picture with an arrow so you know which spot we’re talking about.
ulrichreith-sc24spot-31072006arrow.GIF

Again, the spot persisted for a few days and disappeared.

So what to believe? The transition between one solar cycle and the next is very difficult to call as during the transition both magnetically polarized spots can be seen. The newer cycle spots are usually high latitude (>20o) North and South of the solar equator. Solar cycle 23 spots still continue to produce and any SC24 spots so far are barely a pixel in size and very rare.

Solar cycle 24 remains difficult to call definitively at this time, in my view.


The Sun

Recent Comments