Archive for the ‘Solar physics’ Category

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.

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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)
DOI: http://dx.doi.org/10.1051/0004-6361/201424927
(early preview with registration)

ABSTRACT

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Solar cycle 24 enigma: TSI on the rise again

Posted: February 25, 2015 by tallbloke in Solar physics
Tags: ,

The latest results from the TIM/SORCE TSI instrument show that solar cycle 24 hit a peak on Feb 6th at around 1362.3W/m^2. Does anyone think it’ll go any higher?

tim_level3_tsi_24hour_3month_640x480

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In Astronomy & Astrophysics this week is an article of interest to some Talkshop readers. The authors are looking at the little understood variation is solar rotation in the context of peculiar change in recent years. Article has been amended with a new figure kindly provided by  L. Zhang showing more detail.

Figure caption: Yearly values of the N-S asymmetry (N-S)/(N+S) of the solar rotation at latitude 17 deg in 1978-2013 for X-ray flares (blue open circles) and for sunspots (red open circles). The blue (red) filled circles denote 11 year running mean values for flares (sunspots).

Figure caption: Yearly values of the N-S asymmetry (N-S)/(N+S) of the solar rotation at latitude 17 deg in 1978-2013 for X-ray flares (blue open circles) and for sunspots (red open circles).
The blue (red) filled circles denote 11 year running mean values for flares (sunspots).

Letter to the Editor

Solar surface rotation: N-S asymmetry and recent speed-up
L. Zhang, K. Mursula and I. Usoskin
A&A 575 L2 (2015)
DOI: http://dx.doi.org/10.1051/0004-6361/201425169
(open access)

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As regular readers know, I’m interested in small devices for generating trickle charging solutions for batteries out in the cloudy mountains where the sun rarely shines. We’ve looked at potentially useful stirling engine designs before, but I just found this interesting video on Youtube which differs fundamentally from the stirling design, while retaining some of its thermodynamic features.

 

This type of very simple engine is known by various names such as laminar flow, thermo-acoustic, thermal lag etc, but no-on seems to have a fully developed thermodynamic theory of exactly how it works. Unlike classic stirling engines, there is no ‘displacer’ to shunt the working gas from the hot to the cold end in order to drive a cycle of expansion/contraction which then sucks and pushes a power piston which drives a flywheel (or a linear electric motor). It’s more reminiscent in a way of a pulse-jet engine, but with a closed cycle, rather than an open system generating thrust directly from the explosive expansion of combustible gases.

But besides thinking about the way this engine operates as a collection of glass and aluminium parts heated at one end, it put me in mind of the way the Sun ‘pulses’ every eleven years or so. So this is today’s brainstormer. If objects can be set into oscillation by the application of heat (and let’s not forget thermodynamic theory here, whereby atoms and molecules ‘vibrate’ more vigorously as heat is applied to them), then what if the heavy dense metallic hydrogen core of the Sun is set into oscillation by the heat generated in the fusion process? It wouldn’t oscillate so easily in the X-Y plane, because the Sun is rotating, but it is freer to move in the Z axis.
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Solar contiguous activity cycle 23/24

Posted: December 20, 2014 by tchannon in Astrophysics, Solar physics

At first sight this Brazilan paper in Astronomy & Astrophysics is relatively uninteresting if you are familar with sunspot activity, appears to be another general look using waveletts.

Two features strike me as worthy of highlighting

  • a double burst of activity during cycle 23, not obvious from sunspot data alone
  • continuing activity right through the 23/24 transition

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Extract from paper Fig. 5, my highlight of strong X activity post the cycle 23 sunspot peak.

Wavelet analysis of CME, X-ray flare, and sunspot series

M. R. G. Guedes, E. S. Pereira and J. R. Cecatto

A&A 573 A64 (2015)

DOI: http://dx.doi.org/10.1051/0004-6361/201323080

(access with registration, large PDF 17.7MB)

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Repost from Roger Pielke Sr’s weblog. Important this isn’t lost, because it shows a fatal error in Schmidt and Benestad’s paper. A paper still relied on by the IPCC in AR5 to dismiss solar forcing as an important climate variable, five years after Nicola demolished it. Benestad and Schmidt claim they successfully rebutted Scafetta’s exposure of their fatal error, something Scafetta vigorously disproved. We’ll take a look at that part of the controversy later.

Roger Pielke Sr’s original intro:
On July 22 2009 I posted on the new paper on solar forcing by Lean and Rind 2009. In that post, I also referred to the Benestad and Schmidt 2009 paper on solar forcing which has a conclusion at variance to that in the Lean and Rind paper.

After the publication of my post, Nicola Scafetta asked if he could present a comment (as a guest weblog) on the Benestad and Schmidt paper on my website, since it will take several months for his comment to make it through the review process. In the interests of presenting the perspectives on the issue of solar climate forcing, Nicola’s post appears below. I also invite Benestad and Schmidt to write responses to the Scaftta contribution which I would be glad to post on my website.
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Earth proton events as a solar activity measure

Posted: December 4, 2014 by tchannon in Solar physics

A recent Talkshop comment led me to look at a data directory where something tripped a thought

There is an earth affecting proton event dataset running from 1976, named SPE (Solar Proton Event). These are rare and erratic in time.

A very difficult maths problem is pulse density integration, one of the reasons why producing a statistical distribution shape is very hard where the data is sparse and spasmodic.

Image

I’ve faked up  innovated something visual, some kind of meaningful plot. Far from ideal so don’t be misled.

SSN is from SIDC

Taking the natural log of the energy value produces something sane looking, intuitively would be something like that. Added in some missing points for years with no events. Event data is provided to the second via NOAA.

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Gerry Pease has sent us a solar cycle 24 update:

It’s all downhill now for solar cycle 24. Cycle 24 Max (smoothed sunspot number 81.9) appears to have occurred in April, 2014:

Cycle 24 progress (last update December 1, 2014

Cycle 23 Solar Max (smoothed sunspot number 120) was in early 2000:

Solar cycles 23-24 (last update December 1, 2014)

Note the progression from cycle 21 to 24:

Graphical comparison of cycles 21, 22, 23 and 24 (last update December 1, 2014)

Similar cycles 12, 14, and 16 had lower peaks than cycle 24, and similar cycles 10, 12, 13, 14, and 16 all had earlier peaks:

Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update December 1, 2014)

Smoothed solar activity since April is projected to be successively lower each month.

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By Kelly Dickerson for Yahoo News:

ESA-Magnetospheres_600_MThe sun may be partly responsible for lightning strikes on Earth, and scientists think fluctuations in the sun’s magnetic field could be used to predict lightning storms weeks in advance.

The sun’s magnetic field can bend Earth’s own magnetic field, and this twisting and turning may be allowing an influx of high-energy particles into the planet’s atmosphere. These particles can cause a buildup of electric charge that can trigger lightning strikes.

From 2001 to 2006, during a period when the sun’s magnetic field was severely skewing the Earth’s magnetic field, the United Kingdom saw 50 percent more lightning strikes than normal, according to the new study. This severe skewing happens regularly as the sun’s magnetic field shifts. Scientists say this suggests the sun’s magnetic field could be used to predict the occurrence of lightning.

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A new facility here for creating clear air insolation data, without the more involved absorption effects or cloud, etc. needed some testing and so…

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This plot appeared during July 2012[1] after Dr. Hans Jelbring made available hourly data from the Koorin Expedition to Daly Waters, Australia during the astral winter of 1974[2]. A new plot trace has been added, computed by a new dynamic language[3] library, a wrapper around an unaltered version of NREL SOLPOS[4]. This produces an output value for one point in time, the plots here were created by a program feeding in different parameters, producing a time series, all very simple.

This result is similar to a result with data from Chilbolton Observatory, England from a Kip & Zonnen CNR4 net pyranometer / pyrgeometer[5]. Around 22% of inward solar radiation is absorbed by the atmosphere in excess of that computed by SOLPOS.

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Nicola Scafetta has emailed me to let us know he has a new paper in press which adresses critiques of our solar-planetary theory. I can’t do justice to presenting this work by illustrating this post with figures from the paper using my cellphone, but this a seriously impressive piece of work which Nicola generously shares with Talkshop readers via a link below the break. Nicola writes:

I just would like to share my latest paper
 
Nicola Scafetta, 2014. Discussion on the spectral coherence between planetary, solar and climate  oscillations: a reply to some critiques.

Astrophysics and Space Science in press.

http://link.springer.com/article/10.1007%2Fs10509-014-2111-8

For those who followed this research, the paper strongly rebuts some interesting critiques of the planetary theory of solar and climate variation made by Holm andCauquoin et al. that emerged in the literature during the first months of the 2014. (It also rebuts the very improper and unprofessional criticism made by Anthony Watts)

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Fig.14. 361-day moving average of the integrated flux in the reconstruction and in UARS and SORCE SSI between a) 120 and 180 nm, b) 180 and 250 nm, c) 250 and 300 nm, and d) 300 and 410 nm. The UARS and SORCE time series are normalized to the reconstruction at the 1996 and 2008 solar cycle minima, respectively. The dashed lines indicate the uncertainty range of the reconstruction.

 

Reconstruction of total and spectral solar irradiance from 1974 to 2013 based on KPVT, SoHO/MDI, and SDO/HMI observations
K. L. Yeo, N. A. Krivova, S. K. Solanki, and K. H. Glassmeier

18 page PDF available on registration with Astronomy & Astrophysics
http://dx.doi.org/10.1051/0004-6361/201423628

ABSTRACT

  • Context. Total and spectral solar irradiance are key parameters in the assessment of solar influence on changes in the Earth’s climate.
  • Aims. We present a reconstruction of daily solar irradiance obtained using the SATIRE-S model spanning 1974 to 2013 based on full-disc observations from the KPVT, SoHO/MDI, and SDO/HMI.

 

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EVIDENCE OF LENGTH OF DAY (LOD) BIDECADAL VARIABILITY
CONCURRENT WITH THE SOLAR MAGNETIC CYCLES
Milivoje A. Vukcevic M.Sc
http://hal.archives-ouvertes.fr/hal-01071375/document

Abstract: Number of factors ranging from global atmospheric and oceans circulation to the plate tectonic movements affects the length of day (LOD) on different time scales. Existence of a coincidental or causal correlation between the solar magnetic oscillations and the secular LOD changes is demonstrated.

 

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Michele left a comment on suggestions but the surprise came later

Big Ar 2192 and flare X1.1 + CME

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Note the Solex date: 14th October 2014, today is the 19th.

I looked at the Spaceweather archive for the 14th and of course the authors did not know what was about to happen

SOLAR SECTOR BOUNDARY CROSSING: High-latitude auroras are possible on Oct. 14th when Earth crosses through a fold in the heliospheric current sheet. This is called a “solar sector boundary crossing,” and NOAA forecasters estimate a 25% chance of polar geomagnetic storms when it occurs.

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This not going to please a certain name.

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Modelling total solar irradiance since 1878 from simulated magnetograms
M. Dasi-Espuig, J. Jiang, N. A. Krivova, and S. K. Solanki
Received 27 May 2014 / Accepted 5 August 2014

Astronomy & Astrophysics, Volume 570, October 2014

DOI: 10.1051/0004-6361/201424290
(access with registration)

ABSTRACT

Aims. We present a new model of total solar irradiance (TSI) based on magnetograms simulated with a surface flux transport model (SFTM) and the Spectral And Total Irradiance REconstructions (SATIRE) model. Our model provides daily maps of the distribution of the photospheric field and the TSI starting from 1878.

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The size of the sun is of critical importance to solar studies yet this is poorly known, let alone if and how the size varies over time. Paper published this week in Astronomy & Astrophysics.

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Fig.1. Left: solar radius measurements (red symbols) made since the seventeenth century (Rozelot & Damiani 2012). The mean value of all these measurements is close to 960 arcsec. Right: focus on solar radius measurements made since 1970. …

Fig.2. Evolution of the solar radius variations over time for ground instruments (Solar Astrolabe, DORAYSOL and SODISMII monthly mean at 782.2 nm), balloon experiment (SDS), and space instrument (MDI) vs. daily sunspot number time-series. For each series, the mean has been taken as reference value.

Fig.2. Evolution of the solar radius variations over time for ground instruments (Solar Astrolabe, DORAYSOL and SODISMII monthly mean at 782.2 nm), balloon experiment (SDS), and space instrument (MDI) vs. daily sunspot number time-series. For each series, the mean has been
taken as reference value.

 

Ground-based measurements of the solar diameter during the rising phase of solar cycle 24
M. Meftah, T. Corbard, A. Irbah, R. Ikhlef, F. Morand, C. Renaud, A. Hauchecorne, P. Assus, J. Borgnino, B. Chauvineau, M. Crepel, F. Dalaudier, L. Damé, D. Djafer, M. Fodil, P. Lesueur, G. Poiet, M. Rouzé, A. Sarkissian, A.Ziad, and F. Laclare

Paper access is available with registration.

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Solar timeline [image credit: Wikipedia]

Solar timeline
[image credit: Wikipedia]


This is a follow-on from another recent Talkshop post:

The principal cause of bi-decadal climatic variation – The Hale cycle, or something else?

The subject is a paper that appeared in 2009 which relates to the discussion.
Hopefully the following abstract of it speaks for itself.

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Solar cycle forecasts

Posted: September 21, 2014 by tchannon in Solar physics

 

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This is based on the data provided from the “Solar Cycle Progression” web page, “Provided by the NOAA/Space Weather Prediction Center” except substantial data post processing has been done.

The datasets have been heavily normalised but the F10.7 earth distance problem (or something of a similar origin) has been partially compensated before normalisation.

Normalising brought the three datasets closer to the same.

Two sunspot data r2 > 0.98, SWO/F10.7 r2 > 0.93

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Active solar regions [image credit: NASA/Goddard]

Active solar regions
[image credit: NASA/Goddard]


New research claims to offer ‘a new set of observations to explore the drivers of solar activity beyond only sunspots.’

The researchers say they have found ‘a new marker to track the course of the solar cycle — brightpoints, little bright spots in the solar atmosphere that allow us to observe the constant roiling of material inside the sun.’

“Thus, the 11-year solar cycle can be viewed as the overlap between two much longer cycles,” said Robert Leamon, co-author on the paper at Montana State University in Bozeman and NASA Headquarters in Washington.

More here: 'Brightpoints': New clues to determining the solar cycle — ScienceDaily.

An important new(ish) paper from a team including Ken McCracken looks at the likely continuing slowdown in solar activity:

McC-etal-fig3

CharlesW. Smith1,2, K. G. McCracken3, Nathan A. Schwadron1,2, and Molly L. Goelzer2,4
1Physics Department, Space Science Center, University of New Hampshire, Durham, New Hampshire, USA, 2Institute for
the Study of Earth, Oceans and Space, University of New Hampshire, Durham, New Hampshire, USA, 3Institute of Physical
Science and Technology, University of Maryland, College Park, Maryland, USA, 4Department of Chemical Engineering,
University of New Hampshire, Durham, New Hampshire, USA

Abstract
Recent papers have linked the heliospheric magnetic flux to the sunspot cycle with good
correlation observed between prediction and observation. Other papers have shown a strong correlation
between magnetic flux and solar wind proton flux from coronal holes. We combine these efforts with
an expectation that the sunspot activity of the approaching solar minimum will resemble the Dalton or
Gleissberg Minimum and predict that the magnetic flux and solar wind proton flux over the coming decade
will be lower than at any time during the space age. Using these predictions and established theory, we
also predict record high galactic cosmic ray intensities over the same years. The analysis shown here is a
prediction of global space climate change within which space weather operates. It predicts a new parameter
regime for the transient space weather behavior that can be expected during the coming decade.

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