Questions for Dr. L Svalgaard

[lsvalgaard]

Jan 21, 2011 16:57:17 GMT vukcevic said:

Dr. S.
These are images of magnetic cloud (flux rope)
wwwppd.nrl.navy.mil/prediction/cloud_movie.gif
and the internal structure
ase.tufts.edu/cosmos/view_picture.asp?id=910
Since the magnetic field intensity within is s much higher than the magnetic field of the solar wind in the surrounding areas, do:
- magnetic shock waves move (push) solar wind particles out of the way ?
- SW particles are sucked in by the stronger magnetic field ?

The magnetic field within is not much higher than the magnetic field in the ambient solar wind. It is often even smaller. What happens is that the cloud will compress the solar wind in front of it and that will increase the magnetic field and density. SW particles are not pushed out of the way or sucked in, but are 'scooped up' and travel along with the cloud.

[lsvalgaard]

Jan 22, 2011 10:09:47 GMT vukcevic said:

I was only quoting
wind.nasa.gov/mfi/team_science.html
solar.physics.montana.edu/lundberg/

misquoting

[dh7fb]

Dr. Svalgaard: We see a huge CH ( 435) with an area of about 15% of visible disk and also a great southern PCH. In literature ( articles.adsabs.harvard.edu//full/1993SoPh..148...61D/0000062.000.html ) is written a strong inverse connection between the size of CH's and the SSN and also a connection between the cycle progression and the size of CH's. Do you think the current visible huge CH's are a hint for an ongoing further reduction of the SSN in SC24 and also for a very weak progression as written here: www.springerlink.com/content/kl3631613j021352/
where the authors found a correlation between CH-size and the 6 years later forecast?

[lsvalgaard]

Jan 31, 2011 9:53:58 GMT dh7fb said:

Dr. Svalgaard: We see a huge CH ( 435) with an area of about 15% of visible disk and also a great southern PCH. In literature ( articles.adsabs.harvard.edu//full/1993SoPh..148...61D/0000062.000.html ) is written a strong inverse connection between the size of CH's and the SSN and also a connection between the cycle progression and the size of CH's. Do you think the current visible huge CH's are a hint for an ongoing further reduction of the SSN in SC24 and also for a very weak progression as written here: www.springerlink.com/content/kl3631613j021352/
where the authors found a correlation between CH-size and the 6 years later forecast?

There is a difference between a statistical result and what happens on any given day: the Sun is a messy place. The northern polar cap coronal hole has largely disappeared and the magnetic field there has almost reversed. This process is 'episodic' and proceed in jerks. The huge hole visible right now is of the same polarity as the polar hole that has gone away and may actually move to the pole and reestablish the polar hole. A wild speculation is that the coronal hole is actually the polar hole that has slithered down in latitude. I don't actually think so, but some people might entertain that idea. [you heard it first here ;D ]

[af4ex]

Jan 31, 2011 14:49:48 GMT lsvalgaard said:

Jan 31, 2011 9:53:58 GMT dh7fb said:

Dr. Svalgaard: We see a huge CH ( 435) with an area of about 15% of visible disk and also a great southern PCH. In literature ( articles.adsabs.harvard.edu//full/1993SoPh..148...61D/0000062.000.html ) is written a strong inverse connection between the size of CH's and the SSN and also a connection between the cycle progression and the size of CH's. Do you think the current visible huge CH's are a hint for an ongoing further reduction of the SSN in SC24 and also for a very weak progression as written here: www.springerlink.com/content/kl3631613j021352/
where the authors found a correlation between CH-size and the 6 years later forecast?

There is a difference between a statistical result and what happens on any given day: the Sun is a messy place. The northern polar cap coronal hole has largely disappeared and the magnetic field there has almost reversed. This process is 'episodic' and proceed in jerks. The huge hole visible right now is of the same polarity as the polar hole that has gone away and may actually move to the pole and reestablish the polar hole. A wild speculation is that the coronal hole is actually the polar hole that has slithered down in latitude. I don't actually think so, but some people might entertain that idea. [you heard it first here ;D ]

I understand that pole reversal is a normal part of the 22-year Hale cycle. If what we're observing really is the pole reversal, is it occurring at the expected phase of SC24?

This chart suggests that it normally occurs somewhere towards the end of the first half of the cycle:

[lsvalgaard]

Jan 31, 2011 16:24:02 GMT af4ex said:

Jan 31, 2011 14:49:48 GMT lsvalgaard said:

There is a difference between a statistical result and what happens on any given day: the Sun is a messy place. The northern polar cap coronal hole has largely disappeared and the magnetic field there has almost reversed. This process is 'episodic' and proceed in jerks. The huge hole visible right now is of the same polarity as the polar hole that has gone away and may actually move to the pole and reestablish the polar hole. A wild speculation is that the coronal hole is actually the polar hole that has slithered down in latitude. I don't actually think so, but some people might entertain that idea. [you heard it first here ;D ]

I understand that pole reversal is a normal part of the 22-year Hale cycle. If what we're observing really is the pole reversal, is it occurring at the expected phase of SC24?

This chart suggests that it normally occurs somewhere towards the end of the first half of the cycle:

There is the nagging question about 'what' the polar fields are. Where do you measure them? The operational definition I gave many years ago is that the polar fields are what we measure in the polemost aperture of the Wilcox Solar Observatory instrument seems a reasonable one. See: www.leif.org/research/Cycle%2024%20Smallest%20100%20years.pdf . In para [7] we note that the polar fields so defined change about 18 months before all of the old polarity has been reversed, so everything is still sort of normal. The 'real' reveraal is still 1.5 years away, and there could be several such reversals before the new fields are firmly established. Too early [and too messy] to draw conclusions yet.

[france]

Jan 31, 2011 17:05:40 GMT lsvalgaard said:

Jan 31, 2011 16:24:02 GMT af4ex said:

I understand that pole reversal is a normal part of the 22-year Hale cycle. If what we're observing really is the pole reversal, is it occurring at the expected phase of SC24?

This chart suggests that it normally occurs somewhere towards the end of the first half of the cycle:

There is the nagging question about 'what' the polar fields are. Where do you measure them? The operational definition I gave many years ago is that the polar fields are what we measure in the polemost aperture of the Wilcox Solar Observatory instrument seems a reasonable one. See: www.leif.org/research/Cycle%2024%20Smallest%20100%20years.pdf . In para [7] we note that the polar fields so defined change about 18 months before all of the old polarity has been reversed, so everything is still sort of normal. The 'real' reveraal is still 1.5 years away, and there could be several such reversals before the new fields are firmly established. Too early [and too messy] to draw conclusions yet.

Hello Dr Svalgaard,

If I don't make an error of interpretation about what you wrote : the maximum could begun on about july 2011 ?

[af4ex]

> (label on the plot) ... usable daily polar field measurements ...
Vuk, please explain what these are and how they're obtained. Thanks.

[lsvalgaard]

Feb 1, 2011 11:14:16 GMT vukcevic said:

Here
www.vukcevic.talktalk.net/LFC6.htm
I keep regular update of the polar field; the reduction has accelerated during last couple of months. Extrapolation (dotted line) is the extension of the (6th degree) trend line.

UPDATE:
details are on the WSO webpage:
wso.stanford.edu/Polar.html

Is that a question for me?

[af4ex]

Feb 1, 2011 15:01:37 GMT lsvalgaard said:

Is that a question for me?

I was trying to understand the term "usable daily polar field measurements". Can you explain that for us, Dr. S?

Thanks

[lsvalgaard]

Feb 1, 2011 20:17:45 GMT af4ex said:

Feb 1, 2011 15:01:37 GMT lsvalgaard said:

Is that a question for me?

I was trying to understand the term "usable daily polar field measurements". Can you explain that for us, Dr. S?

Thanks

We measure the polar fields every day when the sky is clear. However, clouds and other things might still interfere with the measurements. A small amount of 'quality control' is performed to weed out the worst outliers. The rests are 'usable'.

[af4ex]

@dr. S.
> A wild speculation is that the coronal hole is actually the
> polar hole that has slithered down in latitude. I don't
> actually think so, but some people might entertain that idea.
> [you heard it first here ]

... carrying that speculation a bit further, is it possible that the coronal hole blob that we see on the far side (below), is "slithering" northward?

Is that how solar pole reversal works?

This happens during every cycle, so what does it look like when it's happening? Or is it too slow or too diffuse to perceive while it's going on?

Attachments:

[lsvalgaard]

Feb 3, 2011 14:32:28 GMT af4ex said:

@dr. S.
> A wild speculation is that the coronal hole is actually the
> polar hole that has slithered down in latitude. I don't
> actually think so, but some people might entertain that idea.
> [you heard it first here ]

... carrying that speculation a bit further, is it possible that the coronal hole blob that we see on the far side (below), is "slithering" northward?

Is that how solar pole reversal works?

This happens during every cycle, so what does it look like when it's happening? Or is it too slow or too diffuse to perceive while it's going on?

There are some people that believe something like that [that the dipole 'rotates' in latitude]. Google 'evidence solar dipole rotation 4.31' and select the first entry shown. Personally I don't think so.

[solarlux]

Dr. Svalgaard,

I work in the radiation effects area supporting spacecraft development and follow with interest your work in developing prediction models for solar conditions that influence space weather. Less pertinent to my field of work yet intriguing to me is the study of long-term TSI variability and its implications to climate research.

Papers by Lockwood et al. (1992) and Giamapapa et al. (2006) report on TSI trending of sun-similar stars and suggest that our star may be "in an unusually steady phase compared to similar stars" (Lockwood).

Kopp's recent GRL paper highlights limitations regarding TSI sensor stability & accuracy and concludes with a warning that "[T]he current database is too short and imprecise to establish the magnitude of long-term irradiance changes, or to alleviate conflicting claims of irradiance variations driving significant climate changes in recent decades."

Do you concur with Kopp's disconcertment? Is the assumption of a consistently flat TSI baseline tenuous given our relatively short period of sampling? And might this concern be heightened by indications that nominal TSI variation is 1/10 too small to account for the LIA?

[lsvalgaard]

Feb 3, 2011 18:07:50 GMT solarlux said:

Dr. Svalgaard,

I work in the radiation effects area supporting spacecraft development and follow with interest your work in developing prediction models for solar conditions that influence space weather. Less pertinent to my field of work yet intriguing to me is the study of long-term TSI variability and its implications to climate research.

Papers by Lockwood et al. (1992) and Giamapapa et al. (2006) report on TSI trending of sun-similar stars and suggest that our star may be "in an unusually steady phase compared to similar stars" (Lockwood).

Kopp's recent GRL paper highlights limitations regarding TSI sensor stability & accuracy and concludes with a warning that "[T]he current database is too short and imprecise to establish the magnitude of long-term irradiance changes, or to alleviate conflicting claims of irradiance variations driving significant climate changes in recent decades."

Do you concur with Kopp's disconcertment? Is the assumption of a consistently flat TSI baseline tenuous given our relatively short period of sampling? And might this concern be heightened by indications that nominal TSI variation is 1/10 too small to account for the LIA?

I basically concur with Kopp, that there is no evidence of any long-term changes from the direct data. The large changes since the LIA that were suggested by studies of stars are not secure. The stars in the older studies were not 'sun-like' enough.
My own opinion is that the sun is right now where it was 108 years ago and that TSI should also be. A reconstruction that does not show that has problems, I would surmise, and must explain why not.