February solar data shows the Sun to still be slumping – but NASA says 'twin peaks' may happen

The data from SWPC is in, and it is lethargic at best. Sunspot numbers took a hit, down to about 42,  a delta of ~50 lower compared to the red prediction line.

Latest Sunspot number prediction

10.7 cm solar radio flux took a similar hit: 

Latest F10.7 cm flux number prediction

The Ap Geomagnetic index was up slightly, but still anemic….

Latest Planetary A-index number prediction

And the most interesting indicator, the plot of solar polar fields, shows a clear zero line crossing, suggesting that Solar max has been reached:

Solar Polar Fields – Mt. Wilson and Wilcox Combined -1966 to Present

Image from Dr. Leif Svalgaard – Click the pic to view at source

Though in spite of that, NASA is now suggesting a “double peak”:

Solar Cycle Update: Twin Peaks?

Something unexpected is happening on the sun. 2013 is supposed to be the year of Solar Max, but solar activity is much lower than expected. At least one leading forecaster expects the sun to rebound with a double-peaked maximum later this year.

The quiet has led some observers to wonder if forecasters missed the mark. Solar physicist Dean Pesnell of the Goddard Space Flight Center has a different explanation:

“This is solar maximum,” he suggests. “But it looks different from what we expected because it is double peaked.”

Conventional wisdom holds that solar activity swings back and forth like a simple pendulum.  At one end of the cycle, there is a quiet time with few sunspots and flares.  At the other end, Solar Max brings high sunspot numbers and solar storms. It’s a regular rhythm that repeats every 11 years.

Reality, however, is more complicated. Astronomers have been counting sunspots for centuries, and they have seen that the solar cycle is not perfectly regular. For one thing, the back-and-forth swing in sunspot counts can take anywhere from 10 to 13 years to complete; also, the amplitude of the cycle varies.  Some solar maxima are very weak, others very strong.

Pesnell notes yet another complication: “The last two solar maxima, around 1989 and 2001, had not one but two peaks.”  Solar activity went up, dipped, then resumed, performing a mini-cycle that lasted about two years.

The same thing could be happening now.  Sunspot counts jumped in 2011, dipped in 2012, and Pesnell expects them to rebound again in 2013: “I am comfortable in saying that another peak will happen in 2013 and possibly last into 2014,” he predicts.

Another curiosity of the solar cycle is that the sun’s hemispheres do not always peak at the  same time.  In the current cycle, the south has been lagging behind the north.  The second peak, if it occurs, will likely feature the southern hemisphere playing catch-up, with a surge in activity south of the sun’s equator.

Twin Peaks (shortfall, med)

Recent sunspot counts fall short of predictions. Credit: Dr. Tony Philips & NOAA/SWPC [full plot]

Pesnell is a leading member of the NOAA/NASA Solar Cycle Prediction Panel, a blue-ribbon group of solar physicists who assembled in 2006 and 2008 to forecast the next Solar Max. At the time, the sun was experiencing its deepest minimum in nearly a hundred years.  Sunspot numbers were pegged near zero and x-ray flare activity flat-lined for months at a time.  Recognizing that deep minima are often followed by weak maxima, and pulling together many other threads of predictive evidence, the panel issued this statement:

“The Solar Cycle 24 Prediction Panel has reached a consensus. The panel has decided that the next solar cycle (Cycle 24) will be below average in intensity, with a maximum sunspot number of 90. Given the date of solar minimum and the predicted maximum intensity, solar maximum is now expected to occur in May 2013. Note, this is not a unanimous decision, but a supermajority of the panel did agree.”

Given the tepid state of solar activity in Feb. 2013, a maximum in May now seems unlikely.

“We may be seeing what happens when you predict a single amplitude and the Sun responds with a double peak,” comments Pesnell.

Incidentally, Pesnell notes a similarity between Solar Cycle 24, underway now, and Solar Cycle 14, which had a double-peak during the first decade of the 20th century. If the two cycles are in fact twins, “it would mean one peak in late 2013 and another in 2015.”

No one knows for sure what the sun will do next.  It seems likely, though, that the end of 2013 could be a lot livelier than the beginning.

Author: Dr. Tony Phillips |

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kadaka (KD Knoebel)

But what happened to Killer Bob?
(And why did that immediately pop up from the grey matter? It’s been decades.)

March (SIDC) SSN number (I provisionally calculated) so far has started well, hovering around 70, which would suggest a possible second peak (previous one Nov.2011), but the spots are minnows
http://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_4500.jpg
Arithmetic sum of the polar magnetic fields >(N+S)</a doesn’t indicate an imminent SC24 max

johnmarshall

Certainly getting cooler. Perhaps it is the sun.(Sarc off)

It's the sun, stupid!

I do not think there has ever been a “twin peaks” solar cycle before, so I think an adolescent boy must be running NASA.
This is an extraordinarily weak cycle, and may be of normal length but very weak as this is the first modern solar cycle with a Livingston and Penn efect (see solar page on WUWT),

Incidentally, Pesnell notes a similarity between Solar Cycle 24, underway now, and Solar Cycle 14, which had a double-peak during the first decade of the 20th century.
How many peaks did cycle 14 have: http://www.solen.info/solar/cycl14.html

Tucker

From the article:
Pesnell is a leading member of the NOAA/NASA Solar Cycle Prediction Panel, a blue-ribbon group of solar physicists who assembled in 2006 and 2008 to forecast the next Solar Max. At the time, the sun was experiencing its deepest minimum in nearly a hundred years. Sunspot numbers were pegged near zero and x-ray flare activity flat-lined for months at a time. Recognizing that deep minima are often followed by weak maxima, and pulling together many other threads of predictive evidence, the panel issued this statement:
“The Solar Cycle 24 Prediction Panel has reached a consensus. The panel has decided that the next solar cycle (Cycle 24) will be below average in intensity, with a maximum sunspot number of 90. Given the date of solar minimum and the predicted maximum intensity, solar maximum is now expected to occur in May 2013. Note, this is not a unanimous decision, but a supermajority of the panel did agree.”
*************************************************
Question for Anthony. It states that Pesnell was on the panel in 2006 and 2008, and that they selected a SS number of 90. That makes it seem as if they selected the number 90 in either 2006 or 2008, when my recollection is that the final number was selected in late 2009 or 2010. These two paragraphs seem slightly revisionist in nature given the timing in it.

We’re in for interesting times. Thanks Anthony, particularly for noting the crossing of the polar magnetic fields.

Tom in Florida

For newer readers and those with short memories, the esteemed Dr Svalgaard was a member of that panel and did not agree with the official number of 90. He predicted that number to be 72.

Jeff L

I think it is worth noting that the 2nd peak of the last cycle was smaller than the initial peak so if we are using the past cycle as an analog, it would stand to reason that a 2nd peak in this cycle would probably have a lower smoothed amplitude than the initial one. To achieve that, we would 1st need to see some drop from the current levels of activity.
It was refreshing to see Dr. Phillips be candid in the lack of understanding of exactly what may happen next. Leif, David, your thoughts on Dr. Phillips commentary?

EW3

The folks doing the solar predictions remind me of Washington economists that turn a reduction in the increase in spending into a “cut”.

tonyc

Another scientist with no fundamental understanding of how the sun works making another guess about the main source of warmth for the Earth. Yet, the science is settled.

TRBixler

Something wrong with the leaves in my teacup. But I am sure if I add a little more tea and swirl it a bit my “science” of a double peak will work out (super majority of consensus ) . 50 and falling.

Frank

“Incidentally, Pesnell notes a similarity between Solar Cycle 24, underway now, and Solar Cycle 14, which had a double-peak during the first decade of the 20th century. If the two cycles are in fact twins, “it would mean one peak in late 2013 and another in 2015.”
Is ths true? The SC14 was not a “double Peak-Type” but a “Sixpack-Type” ( http://kaule.ath.cx:9001/uploads/sc1424.gif ). The picture compares the “Waldmeier-discontinuity adjusted” SC14 with the SC24 as far as it happend. Not a strong similarity, not in the accumulated activity and also not in the shape.

Emmanuel from France

Hi, still reading this fantastic blog every day, for more than 5 years now.
One question : can there be a connexion between 10 mph temps (i.e. stratospheric temps) above both poles and solar activity ?
There seems to be a kind of “hole” of very low temps just above the Groenland, where a record cold was approached a couple of days ago, see :
http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=10&carte=1
Temps are in celsius degrees : -76C = -105F.
I know you don’t really like weather, since weather is not climate 🙂 but next week will see a major cold and snow storm for all of Europe, even reaching north of Africa… in march.
Absolutely unknown for a 13 of march.
The very early cold and snow storm that happened here in western Europe last october have been connected to very low temps by meteorologists.
Thanks a lot for your reactions and, maybe, your answers to my question.

It is quite interesting to see that NASA is now forced to theorize a statistical “long shot” in order to keep from admitting that their previous solar forecasts are looking to be in error. It’s similar to a poker player betting on pulling an inside straight – it can happen, but the great majority of players who bet that way lose badly.
But this also means that we are now poised at one of those fascinating “hinge points” in the data. For most of the time, those of us who pay attention to these cycles know that the predictions being made will take years and years to play out. But now – either the spots will double peak relatively soon (by the end of the year) or else a decline will set in and we’ll start heading back to the solar minimum. The data will tell us which, and in terms of this particular field, we will know fairly soon.
It strikes me that another reason for postulating a double peak is the difficulty of dealing with the consequences, both theoretically and in the real world, of a cycle which just fades away this quickly. I think I can see why trying to draw an inside straight looks like the best bet the mainline theorists have left.

tgmccoy

March 6, 2013 at 6:14 am
May be they mean this “Twin Peaks?”
http://en.wikipedia.org/wiki/Twin_Peaks
Implying things are not as the seem?
NASA Scientists wandering and babbling incoher…
Never mind….

Barry Cullen

NOAA/NASA have been 100% wrong on their projections for cycle 24. They appear to be challenging Paul Ehrlich’s, Hansen’s, Mann’s, et al predictions record.

Harry van Loon

Obviously, sunspot forecasts are not based on anything better than extrapolation. The smoothed max is already behind us, some time in early 2012.

Edim

“it would mean one peak in late 2013 and another in 2015.”
I agree, this cycle has not peaked yet (it’s somewhat arbitrary anyway). It’s a weak (and that means long) cycle, the next minimum not before ~2021.
http://solarscience.msfc.nasa.gov/images/bfly.gif
All cycles have ‘messy’ plateaus.

Eliza

If I recall Hathaway et al from NASA predicted a max SSN of 150-170 for cycle 24 before it started and has been revising downwards EVERY TIME since then. His theory was completely shot.

Resourceguy

Sorry, but consensus forecasting is NOT science. If it were we would not have quantum mechanics and the ether theory would still be enforced today.

Tucker says:
March 6, 2013 at 5:01 am
It states that Pesnell was on the panel in 2006 and 2008, and that they selected a SS number of 90. That makes it seem as if they selected the number 90 in either 2006 or 2008, when my recollection is that the final number was selected in late 2009 or 2010. These two paragraphs seem slightly revisionist in nature given the timing in it.
I was on that panel. The final selection was made in May 2009. Pesnell [based on Schatten’s prediction] and I were the only ones in the beginning of the process advocating a low prediction [around 75]. We eventually convinced the other members that a low prediction was in order, although few could stomach a number as low as we advocated, so 90 became a compromise.
Jeff L says:
March 6, 2013 at 5:44 am
your thoughts on Dr. Phillips commentary?
Solar cycle 14 had many peaks as will cycle 24.

O Olson

I remember when cycle 24 was going to be the strongest cycle eeevahhh!

aaron

I’m under the impression that weak cycles often have spurts of high activity. My guess is that we’ll have a long cycle with an early peak, ie a left hand scew, and periodic burst of high activity.

For predicting solar cycles amplitude most solid ‘science’ could be the ‘pseudo-science’.
Here is an extrapolation from 2003, when I had no idea what all of this was about.
http://www.vukcevic.talktalk.net/SSN.htm
So much for the experts. When the solar ‘science’ comes up with more reliable method, I shall switch to it, till then ….

edim wrote: “I agree, this cycle has not peaked yet (it’s somewhat arbitrary anyway). It’s a weak (and that means long) cycle, the next minimum not before ~2021.”
That’s a possibility – but a quick scan of the graphs included in this post reveals another, I think equally likely, possibility. Those graphs show that, at least for the most recent cycles, solar minima tend to occur about 5 – 6 years after the charted crossing point of the north/south magnetic fields. Since that just happened, this would appear to indicate that the next minima will occur in the 2018 – 2019 time frame.
Let me emphasize that I am not proposing this as a certainty, but it appears to be a solid possibility.

jlurtz

I am not against accurate, verified models!! But, it is obvious to me, that [their words]:
“Pesnell is a leading member of the NOAA/NASA Solar Cycle Prediction Panel, a blue-ribbon group of solar physicists who assembled in 2006 and 2008 to forecast the next Solar Max.” ;
They do not have a model of how the Sun operates. In fact, they are just a group of “Blue-ribbon” statisticians. They predict the future based on the past. If they had a reasonable model of the internal workings of the Sun, they would have not missed Cycle 24 six times over.
I would suggest the following new internal Sun model:
1) Fusion takes place on the surface of the Sun’s Core [not in the center]. The center is the waste area of spent fusion [He]. Note: the core is 75% He / 25% H. Outside the core is 75%H / 25%He.
2) Fusion produces heat. The heat rises creating latitude oriented plasma loops [perpendicular to the Suns Equator]. Through these latitude [both north and south] loops runs the major longitude plasma loops that parallel the Sun’s equator. The latitude oriented loops power the longitude loops via magnetic fields. All initially driven by fusion heat: a massive heat engine!
3) As hydrogen is used at the core surface, it must be replaced for new fusion to occur. The replacement process takes about 50 years and is needed every 360 years.
4) The 11 year Sunspot cycle that we see is the movement of the latitude plasma loops over the core surface. We see the core fusion action via interlocked magnetic fields transmitted by plasma currents.
5) The diameter of the Sun should increase every 360 years then decrease for 50 years. More heat/internal pressure, then less heat/internal pressure. Note: since the fusion does not occur in the center of the core, it does not take 100,000 years for the photons to “escape”; they are driven via interaction with the plasma loops.
OK, now attack!!!

In comparing predictions with observations there is an important caveat, namely that the process whose outcome is predicted is still going on in qualitatively the same manner. This may not be the case with the Sun at present.
Here is a plot comparing TSI with the sunspot number and F10.7 http://www.leif.org/research/TSI-not-following-SSN-F107.png TSI has been scaled to match SSN and F10.7 during solar cycle 23 and you can see that in SC24, too few spots and too little F10.7 are observed. My interpretation of this is that the magnetism is there, but not concentrated enough to produce visible spots with attendant F10.7 emission. This is the Livingston&Penn effect in action. So what should the prediction be? if the sunspot number no longer is a good measure for solar activity. I speculate that something like this is not unprecedented, but also happened 400 years ago, so the Maunder Minimum was not a lack of solar activity [and low TSI], but just a lack of visible spots: http://www.leif.org/research/SSN/Svalgaard14.pdf and http://www.leif.org/research/SSN/Svalgaard12.pdf

chris y

Eliza says-
“If I recall Hathaway et al from NASA predicted a max SSN of 150-170 for cycle 24 before it started and has been revising downwards EVERY TIME since then.”
Here is my list of Hathaway predictions for solar cycle 24, and the date they were made. The Hathaway predictions are apparently the definitive choice of the Goddard Space Flight Center.
01/2004- min 1/07, 160 pk
01/2005- min 1/07, 145 pk 2010
01/2006- min 1/07, 145 pk, 2010
01/2007- min 6/07, 145 pk, 2010
03/2008- min 6/08, 130 pk, 2011.5
01/2009- min 1/09, 105 pk, 2012
04/2009- min 4/09, 104 pk, 2013
05/2009- min 5/09, 90 pk, 2013.5
11/2009- min 5/09, <50 pk, 20??
04/2010- min 12/08, 70 pk, 2013.5
06/2010- min 12/08, 65 pk, 2013.5
10/2010- min 12/08, 64 pk, 2013.5
12/2010- min 12/08, 64 pk, 2013.5
04/2011- min 12/08, 62 pk, 2013.5
12/2011- min 12/08, 99 pk, 2013.2
03/2012- min 12/08, 59 pk, 2013.2
05/2012- min 12/08, 60 pk, 2013.2
06/2012- min 05/08, 60 pk, 2013.4
08/2012- min 05/08, 60 pk, 2013.4
09/2012- min 05/08, 76 pk, 2013.9
11/2012- min 05/08, 73 pk, 2013.9
01/2013- min 05/08, 69 pk, 2013.9
02/2013- min 05/08, 69 pk, 2013.9
There is robust confidence that the Hathaway hindcast of SC24 will be dead-certain…

vukcevic says:
March 6, 2013 at 7:25 am
When the solar ‘science’ comes up with more reliable method, I shall switch to it, till then ….
We have a reliable method. Just rely on that [as NASA does].

chris y says:
March 6, 2013 at 7:39 am
“If I recall Hathaway et al from NASA predicted a max SSN of 150-170 for cycle 24 before it started and has been revising downwards EVERY TIME since then.”
Hathaway’s forecast is a description of what the cycle looks like until now combined with a fit to a the average solar cycle and so by definition will change continuously with time, just like the weather forecast will. I’m sure you would prefer a weather forecast based on the latest observations and updated in real time. Or are one of those people that rely on the Farmers’ Almanac?

JM VanWinkle

Has TSI peaked?

Dr. Lurtz says:
March 6, 2013 at 7:34 am
They do not have a model of how the Sun operates. In fact, they are just a group of “Blue-ribbon” statisticians. They predict the future based on the past. If they had a reasonable model of the internal workings of the Sun, they would have not missed Cycle 24 six times over.
You are displaying your ignorance. The prediction of a low cycle is based on an understanding of how the solar dynamo works.
For your new theory: it looks dead on arrival. The radiative interior containing the core is dynamically stable and does not convect [no rising loops]. Energy is transported by slow diffusion taking ~250,000 years.

Silver Ralph

vukcevic says: March 6, 2013 at 7:25 am
Here is an extrapolation from 2003, when I had no idea what all of this was about.
http://www.vukcevic.talktalk.net/SSN.htm
________________________________
Vuk, you have posted that graph many times before.
Could you give us two short paragraphs explaining the modulating factors that produce that graphical prediction of SSNs.
Thanks.
.

Don K

tonyc says:
March 6, 2013 at 5:48 am
Another scientist with no fundamental understanding of how the sun works making another guess about the main source of warmth for the Earth. Yet, the science is settled.
======================
Let’s be fair. The solar weather guys do not claim that sunspot prediction is settled science. Neither do they claim that anyone who differs with them is either a charlatan, a nutcase, or an agent of the devil.
And and far as I can see they are considerably better at prediction than the Climate Change circus.

SAMURAI

It’s looking more and more like the Eddy Grand Solar Minimum could start sooner than anticipated.
This worries the Warmunistas to the core as even the CAGW grant whores admitted in the leaked AR5 report that the SS/GCR/Cloud phenomenon could actually play a role in global climate change.
With no warming into it’s 17th year, no increase in WV for 22 years, OHC basically trending flat since 2003, 100-year severe weather trends at normal levels, sea rise trend at just 11″/century (and slowing), Antarctic ice extents setting records, PDO started its 30-yr cooling phase in 2008, etc., are all “conspiring” (lol) against CAGW Theory.
Coming up with the fabricated HADCRUT4 was too little too late and just bought them a couple of years. HADCRUT3 has already flatlined since January 1997…
Let the squirming begin.

chris y says:
Here is my list of Hathaway predictions for solar cycle 24, and the date they were made. ………
01/2006- min 1/07, 145 pk, 2010

………………
At the time of that prediction Dr. H looked at my ‘pseudo science’ formula and went into trouble to reproduce it; here you can see the graph he plotted
http://www.vukcevic.talktalk.net/HatPlot.htm
had number of standard objections, and dismiss whole shebang as worthless.
Problem that the solar and the climate science have is that “the future ain’t what it used to be”. Yogi Berra

Green Sand

lsvalgaard says: March 6, 2013 at 7:36 am
http://www.leif.org/research/SSN/Svalgaard14.pdf
“My Working Hypothesis”
“• The Maunder Minimum was not a serious deficit of magnetic flux, but
• A lessening of the efficiency of the process that compacts magnetic fields into visible spots
• This may now be happening again
• If so, there is new solar physics to be learned, let us not shy away from that!”

Thanks Leif will watch with increasing interest.

jlurtz

As per the standard “Perfects” whom display their dogma!!!
“You are displaying your ignorance. The prediction of a low cycle is based on an understanding of how the solar dynamo works.”
{Then this model must be wrong and need replacement!! Because they didn’t initially predict is low cycle!!!!!!!!!}
“For your new theory: it looks dead on arrival. The radiative interior containing the core is dynamically stable and does not convect [no rising loops]. Energy is transported by slow diffusion taking ~250,000 years.”
{Standard dogma: no creative thinking here. Standard answer: we are right and you are wrong. If you are so right, why are your predictions so wrong. Your answer will be “not my predictions, another s”. }
{Your criticism ~250,000 years sounds like the static earth theory; you would have been against tectonic plate movement. You are very careful to NOT put forth any new ideas; is this because you don’t have any? You only put forth standard statistical results. }

Theo Goodwin

Leif,
Thanks for stating your position and thanks for the presentations. That is one substantial brown bag lunch that you gave us.

David Corcoran

Dr. Svaalgard: “Or are one of those people that rely on the Farmers’ Almanac?”. How do the UK’s Met Office monster-super-computer-based long term predictions fare against the Farmers’ Almanac? Even if you regard the FA predictions as no more accurate than a coin toss, that still beats the Met Office predictions. The Met Office long term predictions have been comedy gold for the last several years, fervid dreams of global warming that failed to materialize.

All I can say is that our immediate future in solar physics is going to be interesting!

Dr. Lurtz says:
March 6, 2013 at 8:19 am
“You are displaying your ignorance. The prediction of a low cycle is based on an understanding of how the solar dynamo works.”
{Then this model must be wrong and need replacement!! Because they didn’t initially predict is low cycle!!!!!!!!!}

Oh yes we did: http://www.leif.org/research/Cycle%2024%20Smallest%20100%20years.pdf from October 2004. and Schatten [2003]: “The surprising result of these long-range predictions is a rapid decline in solar activity, starting with cycle #24. If this trend continues, we may see the Sun heading towards a “Maunder” type of solar activity minimum – an extensive period of reduced levels of solar activity.”

jlurtz

WHY DOES THE SOLAR ACTIVITY DECLINE???? WHY DOES IT INCREASE???? Not Sunspots, but Solar activity. Not TSI, but high energy UV. Why don’t you get it??? You have stated that the Sun only has as much effect on the Earth’s temperature as CO2. A carefully crafted statement [you are good at those]. Will you admit that the Sun affects the Earth’s temperature, now, or will you wait to say that “I never said the Sun didn’t affect the Earth’s temperature”.
Did you create the Solar Dynamo model?? Or are you just a statistician using others results???

Kip Hansen

Wasn’t Twin Peaks a soap opera?

NASA seems to be basing their predictions on what “they hope” solar activity will be, as compared to “what solar activity levels are expected”. NASA has become a political organization.

Billy Liar

lsvalgaard says:
March 6, 2013 at 4:56 am
How many peaks did cycle 14 have: http://www.solen.info/solar/cycl14.html
It depends strongly on your choice of smoother. By a suitable choice of smoothing period you can make the July 1906 peak appear to be the center of the first peak and the August 1908 peak the center of the second peak. From a cursory examination of the Wolf numbers since 1749 it would appear that the second peak has always been lower than the first.

Barry Cullen

@lsvalgaard; a dynamically stable solar interior just doesn’t make ANY sense, to me. The natural state of fluid matter is turbulent, not laminar, when the energy density is high and there is a sink for that energy, in this case the surface. Just look at the surface of the sun. You’re saying there is a transition from that to non-mixing somewhere in the interior where the energy is being created? C’mon! A dynamically stable interior may make calculations easier but it’s not reality.

Silver Ralph says:
……..
Hi Silver, The two numbers were known to Ptolomy of Alexandria (Jupiter sidereal & Jupiter-Saturn synodic periods)

Dr. Lurtz says:
March 6, 2013 at 8:56 am
the Sun affects the Earth’s temperature
It may have escaped you that the solar cycle, indeed, does produce a solar signal in temperature of the order of 0.1 degrees.
Did you create the Solar Dynamo model?? Or are you just a statistician using others results???
The basic dynamo model was created by Babcock and Leighton in the 1960s and was the basis for our precursor prediction method in 1978. A modern version of the model is by Choudhuri, e.g. http://www.leif.org/EOS/Choudhuri-forecast.pdf usingf input from me and colleagues.