Many people that have have an interest in the interaction between the Sun and Earth have been keeping a watchful eye on several metrics of solar activity recently. The most popular of course has been sunspot watching.
The sun has been particularly quiet in the last several months, so quiet in fact that Australia’s space weather agency recently revised their solar cycle 24 forecast, pushing the expected date for a ramping up of cycle 24 sunspots into the future by six months.
On August 31st, at 23:59 UTC, just a little over 24 hours from now, we are very likely to make a bit of history. It looks like we will have gone an entire calendar month without a sunspot. According to data from NOAA’s National Geophysical Data Center, the last time that happened was in June of 1913. May of 1913 was also spotless.
With the current space weather activity level of the Sun being near zero, and the SOHO holographic imaging of the far side of the sun showing no developing spots that would come around the edge in the next 24 hours, it seems a safe bet to conclude that August 2008 will be the first spotless month since June 1913.
Here is the sun today, at 09:14UTC August 30th:
Click for a very large image
Some people who watch the sun regularly might argue that August wasn’t really spotless, because on August 21st, a very tiny plage area looked like it was going to become a countable sunspot. Here is an amateur astronomer’s photo of the event:
August 21st, 2008 spots – Photo: Pavol Rapavy
But according to solar physicist Leif Svalgaard, who regularly frequents this blog:
According to NOAA it was not assigned a number on Aug.21st nor on Aug.22.
So without an official recognition or a number assigned, it should not be counted in August as actual sunspot.
It has also been over a month since a countable sunspot has been observed, the last one being on July 18th. Since then, activity has been flat. Below is a graph of several solar metrics from the amateur radio propagation website dxlc.com for the past two months:
Click image for original source
They have a table of metrics that include sunspots, and their data also points to a spotless August 2008. See it here: http://www.dxlc.com/solar/indices.html
So unless something dramatic happens on the sun in the next 24 hours, it seems a safe bet that August 2008 will be a spotless month.
Update: As commenter Jim Powell points out,
There was a stretch of 42 spotless days from 9/13/1996 to 10/24/1996. Today we have equaled this period. Check out Jan Janssens spotless days page http://users.telenet.be/j.janssens/Spotless/Spotless.html.
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what is a sun spot?
I got it. Indeed it does. MgII line was a subject of study of the Orbiting Astronomical Observatory-2 for late type stars. UV studies of stars is a whole area of science.
By the time you get from G type stars to M type stars, the absorption line has become an emission line. Might be saying that the blackbody temperature during minimum is falling,
ergo less absorption for our G2V Sun. You could even say that the variablility in the sun is due to wandering in the spectral subtype…. ever so slightly.
Thank you, that is what I was looking for.
Here’s something for everyone to chew on:
http://www.solarcycle24.com/ and check out the trend charts, then look at the solar wind chart 3mo. Seems that a lull in the cyclic swing of things has started. Co-rotating coronal hole closing?
Ok, back to that MgII 242-310 nm graph. It’s been 2 years roughly since the MgII was passed up, so 2 years back to even where the SC23 will finally end. That’s 2010 time.
Roughly, very very roughly. Line of thought only, but I’d say that this Solar Lull is a deep slumber.
It’s nice to have Leif around.
Patient he is often.
And when we post a cranky thought.
He puts it in a coffin.
Actually, I am not angry. I just think you are wrong.
“There has to some physical sense behind the idea and it should build on what we think we know so that it can be falsified”
This is a declaration of faith in the work done so far. I have no such faith. What you are arguing is that there is no intuitive way to get to a connection with sunspots, even though it is very clear from reading the IPCC that the modelers have very limited understanding of clouds and some breakthrough will be required before we do. A breakthrough that we can’t see right now, or we would be able to predict clouds in the models.
You are making an argument similar to one made by the Intelligent Design people, for example, that the eye could never have evolved because it is too hard for a human to concieve of the chain of events that would lead to it in any detail whatsoever.
The physical world is not limited by the human imagination or human reason. You might argue that the scientific method has to continue down the tracks laid by the general direction of science because that is all we have to do science. However, that path is likely to contain many blind alleys in these early days of climate study. We don’t know enough to rule anything out right now.
Yorick (20:20:32) :
What you are arguing is that there is no intuitive way to get to a connection with sunspots, even though it is very clear from reading the IPCC that the modelers have very limited understanding of clouds and some breakthrough will be required before we do.
What have IPCC and modelers and clouds to do with sunspots? You are assuming that their ignorance can be cured by including sunspots in the mix. There is no grounds for such an assumption. you might as well claim that earthquakes cause climate changes and maybe by remote control they also cause sunspots, and your argument is that we don’t know enough to rule anything out right now.
However, that path is likely to contain many blind alleys in these early days of climate study. We don’t know enough to rule anything out right now.
What I claim is that we do know enough to recognize a blind alley when we see one, even if, perhaps, not all of them. You are saying that we don’t know enough to separate the wheat from the chaff, but that does not mean that we must accept all as wheat. Most is chaff so that ought to be our default position.
You are right, Yorick, we do not have 2,000 yrs, 1000 yrs, or even 500 years of climate study to work with. When I look at the information we do have, I think of the evolution of telescopes and detectors: As you go back in time, the resolution loses magnitudes. In the time frame we need most to have superior resolution, we started it with crude lenses and eyeballs.
What other choice do we have but to beat as many paths as possible?
Robert Bateman (21:26:36) :
What other choice do we have but to beat as many paths as possible?
What other paths do you beat, other than the solar one? AGW?
Was the sunspot of aug 21 a visible light sunspot, or was it something else?
What I claim is that we do know enough to recognize a blind alley when we see one, even if, perhaps, not all of them.
I disagree, I guess we are agreed on that much, anyway.
If solar activity stays low and GW takes off like is predicted, then I will have to say you are right, but until that happens, I hope you will forgive me for suspending judgement.
@Leif
How about the Barycentric Path? 😉
Robert Bateman (02:10:24) :
Was the sunspot of aug 21 a visible light sunspot?
Yes, just small.
REPLY: Now waaaaaiiiiiittttttt a minute. Leif you NOW agree that it was a spot rather than a pore than shouldn’t have been counted? – Anthony
Leif,
You ain’t selling out are you?
Leif Svalgaard (06:41:01) :
Robert Bateman (02:10:24) :
Was the sunspot of aug 21 a visible light sunspot?
Yes, just small.
REPLY: Now waaaaaiiiiiittttttt a minute. Leif you NOW agree that it was a spot rather than a pore than shouldn’t have been counted? – Anthony
Mike Bryant (07:01:54) :
Leif,
You ain’t selling out are you?
Hold it, folks. When Robert asked “was the sunspot…” he clearly meant “was whatever was seen…”, and not hung up on detail of it was a pore or a real spot. His question had to do with what wavelength thing bloody thing was visible in, presumably with the aim of finding a reason for the ancients not to have counted it [if they couldn’t see it].
So, clearly, in my response I didn’t press the fine point either.
Here is what Bill Livingston had to say about it in email to me:
William Livingston to leif, Sep 1 (4 days ago)
Reply
Leif,
I don’t know the definition of an ‘active region’. Certainly this was a pore(s). Without penumbrae.
In my own archive of sunspots and pores, for which I do not normally have white light pictures, the pores are distinguished by the greater depth of the quiet sun Fe 15648 compared to the Zeeman components. This is my own criterion and not discussed elsewhere so far as I know.
An interesting feature of pores is that, with the Fe 15648 line, the mag field measurement is independent of seeing (so long as the Zeeman components are visible). This is because the line is always completely split in umbrae. As you know, only the Mt Wilson drawings and our own 15648 obs are capable of accurate mag field measurements in umbrae. SOLIS, SOHO, and Hinode obs tell us nothing about field strength (only flux). See: Solar Phys 239, 41 (2006).
Bill
—-
I defer to Bill: it was a pore.
Should it be counted? That is where different people have different rules. Wolf would not have counted it, NOAA did not call it an ‘active region’, SIDC did count it. If your rule differs from Wolf’s [which is OK] you will just have to adjust your numbers [using a ‘k’ different from 1 in Wolf’s formula R = k (10G+S), that’s all.
Dee Norris (05:29:18) :
How about the Barycentric Path? 😉
I did see the smiley, but that path [from the climate’s POV] is just the solar path, so not different. My question to Robert [and Yorick, I guess] that he did not answer, was “what other path than solar does he beat?”
Yorick (05:12:58) :
[me:] What I claim is that we do know enough to recognize a blind alley when we see one, even if, perhaps, not all of them.
[Yorick:] I disagree, I guess we are agreed on that much, anyway.
If solar activity stays low and GW takes off like is predicted, then I will have to say you are right.
It would seem that you [even now] agree that we can recognize that blind alley, contrary to your statement that we don’t know enough to rule anything out.
So, this Aug 21st sunspot, was it a visible sunspeck that won’t relate to the 150 yr record?
Did we count sunspots that small since 1857 or whenever the unbroken line of records began?
All I care about is that we continue to compare apples to apples.
According to reports, some observatories spotted it.. while others did not. At the time Catania gave it a number, NOAA did not. Looking back NOAA decided to recognize it as a valid sunspot.. That is why the when looking at this data link, the RI average for the month is 0.5.
http://www.swpc.noaa.gov/ftpdir/weekly/RecentIndices.txt
Robert Bateman (09:21:06) :
So, this Aug 21st sunspot, was it a visible sunspeck that won’t relate to the 150 yr record?
Did we count sunspots that small since 1857 or whenever the unbroken line of records began?
All I care about is that we continue to compare apples to apples.
Robert, you may assume that the solar astronomers are not complete morons. And that they have agonized over this problem for 150 years. Here is the story:
When Schwabe discovered the sunspot cycle [and it was brought to a wider attention in von Humboldt’s wildly popular ‘Cosmos’] there was immense interest in this phenomenon. Rudolf Wolf in Switzerland began his own careful count in 1849 and continued until his death in 1893. He had also wrote to astronomers around the world to assist him in getting an unbroken record. He had first thought of measuring the area of all the spots, but discovered that this was impractical and too much work [especially to impose on his collaborators abroad] so settled for a simpler method. He had determined that on average a sunspot ‘group’ of related spots [born and decay as an ensemble] had about 10 spots and thought [correctly] that the group was an important physical aspect of sunspots. To reflect that he devised his famous formula: W = 10 * G + S, where G is the number of groups and S is the number of spots, giving group ten times as much weight as a spot [that is where the ’10’ comes from]. He also discovered that S was very sensitive to what astronomers call ‘seeing’, the constant ‘jitter’ of the image caused by movement of the heated air through which we observe the Sun. This was especially a problem for the smallest spots [the pores], that simply disappeared if the seeing was bad. His solution to this problem was to not count the smallest spots [and even count the biggest spots twice or more – getting the ‘area’ in through the back door, so to speak]. Hoyt and Schatten about a decade ago went so far as to suggest not counting any spots at all, and only count the groups – their famous Group sunspot number. Wolf found that his scheme worked well and that his collaborators could produce reasonable [as judged by Wolf, of course] results, and so was born the Sunspot Number – or as he wanted it called, the Wolf Number. Because it is not a ‘real’ count of spots, but a sort of index, he called it the “Relative sunspot number” [hence its designation by the letter R].
Wolf also scoured the astronomical literature and dug up all the observations that he could find and tried to re-construct the sunspot number from these old observations. This turned out to be a lot harder than he had thought because the observations were done by different people with different telescopes at sites with different seeing [Sunny Italy vs. foggy England]. Wolf worried a lot about the ‘calibration’ of his reconstructed counts. His partial solution to this problem was to introduce a ‘constant’ k [from the German word Konstant] to compensate for the differences: R = k * W. He discovered on several occasions that the numbers he had already published were incorrectly calibrated [this means that he had assigned the wrong ‘k’ to an observer], so the sunspot record kept changing [in 1861 where the numbers were adjusted upwards by 25%, in 1872 when the numbers before 1800 were simply doubled, in the 1880s, …]. Wolf was well aware of the implications of just changing a series that people were already using for correlations of all sorts: the weather, the price of grain, you name it…] so these ‘adjustments’ were not much publicized; he simply publish an adjusted series without too many comments – perhaps hoping that people wouldn’t notice too much.
The reason that Wolf was confident that his adjusted and corrected [‘monkeyed’ with some would say] sunspot number series was an improvement over the raw counts from disparate sources, was that several people around 1845-1855 had discovered that the ‘magnetic needle’ was sensitive to variations in the sunspot number: many spots and the needle’s variations were greater. The Sun’s Far Ultraviolet radiations creates and maintains the ionosphere in which currents flow that create a magnetic field
at the surface of the Earth, adding to the Earth’s own field and changing the direction of a compass needle slightly. They did not know [yet] about the ionosphere and FUV, but the variation of the needle was discovered a long time ago by Graham in London in 1722 and was easy to measure, even with 18th [and 19th] century instruments. wolf devised another famous formula: r = a + b * W, where r was the ‘range’ of the needle’s variation during a day [typically 5-10 arc minutes], W is his Wolf number, and a and b two constants that seemed to vary a bit from station to station. Wolf also asked the observatories to keep track of ‘r’. At the end of each year when Wolf had worked up his Wolf number for the year, he would calculate [a true prediction] the value of ‘r’ for the different observatories well ahead of getting ‘r’ in the mail [no internet then!] from far-away places. He never failed to marvel at [and forcefully point out] how well his prediction worked, because it did. He was almost always right on. This gave him confidence in his adjustments.
Meanwhile, in 1875 Wolf hired an assistant, Alfred Wolfer. Wolfer disagreed with Wolf about counting of small spots and argued that all spots should be counted [no matter how small, even pores]. As long as Wolf was alive, Wolfer did not prevail [although I think he stopped counting big spots twice] and Wolf’s method carried the day. Wolfer had in secret kept two counts: using Wolf’s method and using his ‘all-spot-counted’ method, and had determined that if the all-spot number was multiplied by k = 0.6 they would fir Wolf’s number reasonably well. So, when Wolf died, Wolfer switched to the all-spot method [which is used to this day], but all counts are scaled down by the factor 0.6, in addition to whatever other factor is determined by the size of the telescope, the observer, the location, etc.
Wolfer also calculated the range of the needle [the so-called ‘Declination’] using Wolf’s formula and set of constants a and b, and noted that although it had worked well for Wolf back in the 1860s, the calculated values of r began to drift and the disagreement with the observed values grew [systematically] with time. In addition, the famous and influential geophysicist Sidney Chapman did not care for ’empirical’ adjustments and pooh-poohed the method, pointing out that the variation of a and b with location was not understood and so there were no rigorous theoretical justification for the relationship, and use of the formula was eventually abandoned by the 1920s. This means that we lost the valuable cross-check on the sunspot number that the formula had provided.
So, what was wrong with the formula? It turns out to be two things: First, the magnetic force resulting from the ionospheric current controlled by the Sun is constant [over a large range of latitudes, 15-65 degrees] at any given time [although varies width]. But he deflection of the needle from true North is the resultant of two forces: the constant solar-induced force and the Earth’s own magnetic force, and that latter varies from place to place, from a maximum at the equator to zero at the poles. so, that was one source of variation of a and b. And second, the Earth’s magnetic field is itself slowly decreasing [10% since the time of Wolf], altering one of the two forces in the vector addition that gives us the final deflection. These reason were not known [although they could have been] when the formula was abandoned. If we take these two factors into account, Wolf’s formula works again [he would have been delighted] and we can now see that Wolfer’s 0.6 adjustment was not quite right and that Max Waldmeier who took over the production of the sunspot number in Zurich in 1945 introduced a 20% error in the calibration [due to his inexperience – there is a wonderful anecdote about that his predecessor, Brunner, would not help Waldmeier to get started because as Brunner said “I’m retired and cannot be expected to work anymore”].
When Zurich stopped the sunspot number production in 1980, Brussels took over, with the usual problems of getting the calibration correct – splicing two series with no overlap. Use of the rediscovery that Wolf’s formula works again is being resisted by entrenched institutions and individuals that find it easier to adopt a ‘do nothing’ posture. We can see this in small things as well: the plot at NOAA of the predicted and observed cycle 24 values for the f10.7 flux is wrong, but ‘cannot be changed’. The adopting of 0.5 as August’s official sunspot number is still not changed even after SIDC has admitted that it may be [slightly] in error. The cycle 24 prediction panel has not updated their prediction taking into account the drawn-out minimum of SC23, and on and on.
I hope you find this story of interest. It has many human element, good and sad, as life in general. Science is also a social process.
is constant [over a large range of latitudes, 15-65 degrees] at any given time [although varies with time].
Robert Bateman (10:31:20) :
Looking back NOAA decided to recognize it as a valid sunspot
Not quite correct. NOAA did not change its mind.
From the file you cite, here are the last three months. the last column is the SIDC sunspot number, the penultimate column is the NOAA sunspot number. As you can see it stays at zero. NOA just reports both numbers.
2008 06 4.2 3.1
2008 07 1.0 0.5
2008 08 0.0 0.5
The NOAA ‘region number’ is different from the sunspot number, as I have explained repeatedly. The Aug.21-22 pores did not rise to the level of qualifying for a region number. Different story. Nobody changed anything at any time.
REPLY: I’m going to make a separate post to clear up this confusion. – Anthony
Okay. Since NOAA keeps it’s Aug 21-22 sunspot number at zero, can we then safely say that the last NOAA sunspot was 45 days ago?
Robert Bateman (13:59:19) :
Okay. Since NOAA keeps it’s Aug 21-22 sunspot number at zero, can we then safely say that the last NOAA sunspot was 45 days ago?
Here are the NOAA numbers:
2008 07 16 65 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 17 65 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 18 65 11 10 1 -999 A0.0 0 0 0 0 0 0 0
2008 07 19 66 12 20 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 20 66 11 10 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 21 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 22 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 23 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 24 65 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 25 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 26 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 27 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 28 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 29 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 30 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 07 31 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 01 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 02 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 03 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 04 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 05 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 06 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 07 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 08 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 09 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 10 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 11 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 12 65 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 13 65 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 14 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 15 65 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 16 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 17 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 18 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 19 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 20 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 21 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 22 68 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 23 68 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 24 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 25 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 26 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 27 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 28 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 29 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 30 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 08 31 67 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 09 01 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 09 02 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 09 03 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 09 04 66 0 0 0 -999 A0.0 0 0 0 0 0 0 0
2008 09 05 65 0 0 0 -999 A0.0 0 0 0 0 0 0 0
The last [SESC,NOAA] sunspot number reported was on July 20th.
You get the data for the last quarter here:
http://www.swpc.noaa.gov/ftpdir/indices/quar_DSD.txt
Works for me Leif, thats 45 days all right.
Good work!