Archive for the ‘Solar physics’ Category

Two papers are on the way about a model linking solar field activity and large terrestrial eqarthquakes. h/t to Michele

Studies Suggest Sun Triggers Massive Earthquakes
The sun is triggering the deadliest earthquakes on the planet, including the recent M8.3 earthquake in Chile on September 16, 2015 and deadly tsunami that followed, according to two papers to be published October 5th in New Concepts in Global Tectonics. The papers investigate fluctuations in the magnetic field activity of the sun and found a statistically significant relationship between M8+ earthquakes and the extremes and reversals in magnetism of solar polar magnetic fields.

The team first announced the results in August 2014, and recently used the methods proposed in that study to provide evidence that a recent major earthquake fit the patterns observed in the foundational study. In early 2014, Dr. Christopher Holloman’s team of researchers at The Ohio State University Statistical Consulting Service was able to construct a model that exhibited very strong agreement between solar magnetism patterns and the occurrence of large earthquakes. Dr. Holloman warned that formal testing of the model can only be performed by examining its performance over the next few years, but that the agreement was sufficient to suggest that a relationship likely exists between solar polar fields, or magnetic fields associated with the north and south poles of the sun, and large earthquakes. Now we have a subsequent event that appears to comport with the initial study.


Solar brightness variability, illuminating paper

Posted: September 19, 2015 by tchannon in Solar physics

Tim suspects this paper is important even though it is based largely on modelling. It says the intensity of spectral lines etc. are very important in variability, ultra-violet particularly, moreover there is counter sunspot cycle. This fits with where I think we are going on understanding solar terrestrial linkage.



The role of the Fraunhofer lines in solar brightness variability
A. I. Shapiro S. K. Solanki, N. A. Krivova, R. V. Tagirov, and W. K. Schmutz

Astronomy & Astrophysics, 2015, open access with free registration.

Context. The solar brightness varies on timescales from minutes to decades. A clear identification of the physical processes behind such variations is needed for developing and improving physics-based models of solar brightness variability and reconstructing solar brightness in the past. This is, in turn, important for better understanding the solar-terrestrial and solar-stellar connections.


This grand paper examines many lines of evidence, many well known authors, enjoy the feast


The Maunder minimum (1645–1715) was indeed a grand minimum:
A reassessment of multiple datasets
Ilya G. Usoskin, Rainer Arlt , Eleanna Asvestari, Ed Hawkins, Maarit Käpylä, Gennady A. Kovaltsov, Natalie Krivova, Michael Lockwood, Kalevi Mursula, Jezebel O’Reilly, Matthew Owens, Chris J. Scott, Dmitry D. Sokoloff, Sami K. Solanki, Willie Soon and José M. Vaquero

Astronomy & Astrophysics, accepted July 2015, 19 pages, access on registration

Aims. Although the time of the Maunder minimum (1645–1715) is widely known as a period of extremely low solar activity, it is still being debated whether solar activity during that period might have been moderate or even higher than the current solar cycle #24. We have revisited all existing evidence and datasets, both direct and indirect, to assess the level of solar activity during the Maunder minimum.

Conclusions. We conclude that solar activity was indeed at an exceptionally low level during the Maunder minimum. Although the exact level is still unclear, it was definitely lower than during the Dalton minimum of around 1800 and significantly below that of the current solar cycle #24. Claims of a moderate-to-high level of solar activity during the Maunder minimum are rejected with a high confidence level.


The long descent toward cycle 25

Posted: September 4, 2015 by tchannon in Cycles, Forecasting, Solar physics

Our sometimes contributor Michele has posted an article on his Italian language blog.



Watching solar: The long descent of solar cycle SC24 has started!
(hopefully Google Translate will kick in automatically (see top of page), or use Bing translation)

Do I (Tim) agree with Michele, yes, will be about now.

We have the most uncertain solar situation in living memory.


A simulation of a cross-section of a thread of solar material, called a filament, hovering in the sun's atmosphere [image credit: NAOJ/Patrick Antolin]

A simulation of a cross-section of a thread of solar material, called a filament, hovering in the sun’s atmosphere
[image credit: NAOJ/Patrick Antolin]

Researchers find this works in ‘the same way that a perfectly-timed repeated push on a swing can make it go higher’, as reports:

Modern telescopes and satellites have helped us measure the blazing hot temperatures of the sun from afar. Mostly the temperatures follow a clear pattern: The sun produces energy by fusing hydrogen in its core, so the layers surrounding the core generally get cooler as you move outwards—with one exception.

Two NASA missions have just made a significant step towards understanding why the corona—the outermost, wispy layer of the sun’s atmosphere —is hundreds of times hotter than the lower photosphere, which is the sun’s visible surface [aka the coronal heating problem]


A bit less of this to look forward to? [image credit:]

A bit less of this to look forward to? [image credit:]

Some solar theories will be put to the test in the next few decades by the Sun’s ongoing behaviour patterns.

Is Earth slowly heading for a new ice age? Looking at the decreasing number of sunspots, it may seem that we are entering a nearly spotless solar cycle which could result in lower temperatures for decades. “The solar cycle is starting to decline. Now we have less active regions visible on the sun’s disk,” Yaireska M. Collado-Vega, a space weather forecaster at NASA’s Goddard Space Flight Center, told

But does it really mean a colder climate for our planet in the near future? In 1645, the so-called Maunder Minimum period started, when there were almost no sunspots. It lasted for 70 years and coincided with the well-known “Little Ice Age”, when Europe and North America experienced lower-than-average temperatures. However, the theory that decreased solar activity caused the climate change is still controversial as no convincing evidence has been shown to prove this correlation.


The 'before' version of sunspot numbers [Credit: Wikipedia]

The ‘before’ version of sunspot numbers [Credit: Wikipedia]

This result has been at least half-expected ever since the ‘revision’ of sunspot numbers was announced. The phrase ‘desired outcome’ springs to mind.

The Sunspot Number is a crucial tool used to study the solar dynamo, space weather and climate change, reports It has now been recalibrated and shows a consistent history of solar activity over the past few centuries. The new record has no significant long-term upward trend in solar activity since 1700, as was previously indicated. This suggests that rising global temperatures since the industrial revolution cannot be attributed to increased solar activity.

The analysis, its results and its implications for climate research were made public today at a press briefing at the International Astronomical Union (IAU) XXIX General Assembly, currently taking place in Honolulu, Hawaii, USA.


What happened to the sunspots?

Posted: July 14, 2015 by oldbrew in Solar physics

Giant sunspot group AR1944 in January 2014. [Credit: NASA/SDO]

Giant sunspot group AR1944 in January 2014. [Credit: NASA/SDO]

Communities Digital News explains:

On June 30, 2015 the globally recognized maximum for the current 11-year sunspot cycle was 81.9. On July 1, 2015 that number suddenly leaped all the way up to 116.4!

Stranger still, the current cycle (Cycle 24) fell from being the 7th weakest sunspot maximum since 1749 to being the 4th weakest sunspot maximum. Cycle 24’s sunspot number jumped by 30 percent, yet its ranking dropped by three places. How can that be?


[Image credit: NASA]

[Image credit: NASA]

Another solar theory rolls off the production line – as ever, time will tell if it lives up to its own billing.

A new model of the Sun’s 11-year heartbeat suggests that solar activity will fall by 60 per cent during the 2030s, dropping to conditions last seen during the Maunder minimum, reports Ice Age Now.

Beginning in about 1645, the Maunder minimum corresponded with the severest portion of the last
“Little Ice Age.”


Via Benny Peiser at the GWPF
Image courtesy of

Image courtesy of

Britain could be on the verge of a mini Ice Age as the Sun enters a cooler phase, the Met Office warned yesterday. The last big chill was felt hundreds of years ago when Frost Fairs were held on the frozen River Thames. However the Met Office said the new freeze will not be enough to cancel out the effects of global warming. Met Office’s Hadley Centre, which looks at long term forecasts, said there was a 15-20 per cent chance that we could match the temperatures last seen in 1645-1715 – sometimes called the Little Ice Age – when the River Thames froze over. –Colin Fernandez, Daily Mail, 24 June 2015


Variation in sunspot properties between 1999 and 2014

R. Rezaei1, C. Beck, A. Lagg, J. M. Borrero, W. Schmidt and M. Collados

A&A Volume 578, June 2015 Article Number A43
Published online 01 June 2015
Open access with registration


Aims. We study the variation in the magnetic field strength, area, and continuum intensity of umbrae in solar cycles 23 and 24.

Conclusions. The umbral brightness decreases in the rising stage of a solar cycle, but increases from maximum toward the end of the cycle. Our results do not indicate a drastic change of the solar cycle toward a grand minimum in the near future.

Specifically disagrees with Livingson concluding the weak trending lower is too minor for there to be much change on the horizon.


Level and length of cyclic solar activity during the Maunder minimum as deduced from the active-day statistics
J. M. Vaquero, G. A. Kovaltsov, I. G. Usoskin, V. M. S. Carrasco and M. C. Gallego
A&A, 577 (2015) A71
Published online: 06 May 2015
(open access with registration)



Aims. The Maunder minimum (MM) of greatly reduced solar activity took place in 1645–1715, but the exact level of sunspot activity is uncertain because it is based, to a large extent, on historical generic statements of the absence of spots on the Sun. Using a conservative approach, we aim to assess the level and length of solar cycle during the MM on the basis of direct historical records by astronomers of that time.


This paper published 10th March tries to identify major episodic solar activity by using both 14C and 10BeImage

(note to reader, above x-axis has advancing time running right to left)

Grand solar minima and maxima deduced from 10Be and 14C: magnetic dynamo configuration and polarity reversal
F. Inceoglu, R. Simoniello, M. F. Knudsen, C. Karoff, J. Olsen, S. Turck-Chiéze, B. H. Jacobsen
A&A 577 A20 (2015)
DOI: 10.1051/0004-6361/201424212


Aims. This study aims to improve our understanding of the occurrence and origin of grand solar maxima and minima.
Methods. We first investigate the statistics of peaks and dips simultaneously occurring in the solar modulation potentials reconstructed using the Greenland Ice Core Project (GRIP) 10 Be and IntCal13 14 C records for the overlapping time period spanning between ~1650 AD to 6600 BC.


I’ve included this on the front page because I think the bimodality of solar data is an important matter where this work adds weight to the effect being real.
Open access with registration


A solar 'prominence' [credit: NASA]

A solar ‘prominence’ [credit: NASA]

Not being an expert in such matters I turn to NASA for a brief explanation of terms:

‘The primary source of energy to the Earth is radiant energy from the Sun. This radiant energy is measured and reported as the solar irradiance. When all of the radiation is measured it is called the Total Solar Irradiance (TSI); when measured as a function of wavelength it is the spectral irradiance.’
NASA – Solar Irradiance

The abstract of a new paper suggests there’s a need to take a lot more notice of ‘SSI’ compared to ‘TSI’.
Note in particular its last sentence
‘Therefore, it appears that SSI rather than TSI is a good indicator of the chromospheric activity, and its cycle length dependent variation would be more relevant to the possible role of the Sun in the cyclic variation of the Earth’s atmosphere.’


This failed work is presented as a cautionary tale but nevertheless there might be good parts.

Earlier oldbrew published an article on a theory by Nelson on forecasting the armada of radio propagation conditions. There were not many comments, possibly from the lack of solid further material.

From this paper, we can see why the technique fell at the hurdle. Nevertheless looking at what people were thinking and doing is important.


A resent post by Roger and comments thereon led to my  realising there are misunderstandings on the intepretation of the polar field relationships.

Wilcox Observatory[1] measure and publish a time series of the solar polar magnetic field, a difficult measurement. Started 31st May 1976, data point every 10 days.


Figure 1, straight plot of f10.7 radio noise[3] as a proxy for solar activity and mean solar polar magnetic field[1].

Firstly here are some clarification notes.

The polar field is not the interplanetary field[6] indirectly associated with terrestrial cosmic ray flux. This field at earth roughly follows the F10.7 / sunspot shape, is very noisy.

Neither is it the Livingstone & Penn[2] finding about the change in sunspot magnetic field possibly reducing with time.


Back in 2011. Tim Channon used his cycles analysis software to predict the evolution of the solar polar fields. The basis of the curve he produced is the motion of the gas giant planets, Jupiter, Saturn, Uranus and Neptune. As they orbit the Sun, they force the Sun to move relative to the centre of mass of the entire solar system. We see this motion when astronomers look out into the near cosmos and observe other stars ‘wobbling’. By measuring the wobble with respect to time, they are able to deduce the mass and distance of planets orbiting those stars, even though they are too small and dim to see directly.

Tim found that our Sun’s wobble due to the gas giant planets matched the observational data of the evolution of the Solar polar magnetic fields mentioned in the post put up by Stuart ‘Oldbrew‘ yesterday.

Here’s the plot Tim put up in 2011

Evolution of combined solar polar fields (red) vs motion of Sun relative to barycentre caused by planetary motion

At the time, it looked like the data was going to diverge from the prediction, but read on below the break to see the outcome.


The Sun from NASA's SDO spacecraft

The Sun from NASA’s SDO spacecraft

According to new research entitled: “The crucial role of surface magnetic fields for the solar dynamo”, a prediction method for solar cycles, first proposed decades ago, has been validated:
‘As the dipole field [of the Sun] is the source of the toroidal field of the next cycle, its strength should be a measure of the activity of the next cycle.’ reports:
Sunspots, bursts of radiation and violent eruptions are signs that our sun is permanently active. Researchers have long known that this activity varies in a cycle of around eleven years’ duration. Even if many questions are still unresolved, one thing is certain: magnetic fields which emerge on the surface of our sun from within its depths are the cause of the manifold activities.

Robert Cameron and Manfred Schüssler from the Max Planck Institute for Solar System Research in Göttingen have now proved that it is possible to deduce what the internal mechanism is simply by observing the magnetic processes on the surface. This even allows predictions to be made about the strength of a forthcoming activity cycle.


Back in 1987, Robert M Wilson of NASA’s Space Science Laboratory in Huntsville published this paper in the Journal of Geophysical Research. It’s important to our solar-planetary theory because it shows that the Sun is bi-modal in terms of its solar cycle lengths. They cluster around  periods of a little over ten and a little under twelve years. These periods correlate to the periods of Jupiter-Earth-Venus syzygy cycles and Jupiter’s orbital period respectively. Leif Svalgaard vehemently denied this correlation when I pointed it out to him a few years ago.


The same correlation was noted by independent researcher Timo Niroma in 1989, who conducted his own survey and analysis of solar cycle lengths. He produced this simple ascii-art graphic to present his results.


Solar cycle 4b, support from 10BE proxy

Posted: February 28, 2015 by tchannon in Solar physics

One of the unsolved solar mysteries is the peculiar behaviour around year 1800. The data we have is poor leading to ambiguity on whether a solar sunspot cycle is missing from the record.


Figures from paper. For a legible copy you will need to register and download the PDF.

The lost sunspot cycle: New support from 10Be measurements
C. Karoff, F. Inceoglu, M. F. Knudsen, J. Olsen, A. Fogtmann-Schulz
A&A 575 A77 (2015)
(early preview with registration)