I initially wrote this article using data only from David Archibald, but within a couple of minutes I was given some broader data from Leif Svalgaard, so I have rewritten this to include both resources in the interest of seeing the broader perspective. – Anthony
Last September WUWT covered NASA’s press conference on the state of the sun. One of the announcements was this:
Sept. 23, 2008: In a briefing today at NASA headquarters, solar physicists announced that the solar wind is losing power.
“The average pressure of the solar wind has dropped more than 20% since the mid-1990s,” says Dave McComas of the Southwest Research Institute in San Antonio, Texas. “This is the weakest it’s been since we began monitoring solar wind almost 50 years ago.”
From Wiki:
The solar wind is a stream of charged particles—a plasma—ejected from the upper atmosphere of the sun. It consists mostly of electrons and protons with energies of about 1 keV. The stream of particles varies in temperature and speed with the passage of time. These particles are able to escape the sun’s gravity, in part because of the high temperature of the corona, but also because of high kinetic energy that particles gain through a process that is not well-understood.
The solar wind creates the Heliosphere, a vast bubble in the interstellar medium surrounding the solar system. Other phenomena include geomagnetic storms that can knock out power grids on Earth, the aurorae such as the Northern Lights, and the plasma tails of comets that always point away from the sun.The solar wind is a stream of charged particles—a plasma—ejected from the upper atmosphere of the sun. It consists mostly of electrons and protons with energies of about 1 keV. The stream of particles varies in temperature and speed with the passage of time. These particles are able to escape the sun’s gravity, in part because of the high temperature of the corona, but also because of high kinetic energy that particles gain through a process that is not well-understood.
The solar wind creates the Heliosphere, a vast bubble in the interstellar medium surrounding the solar system. Other phenomena include geomagnetic storms that can knock out power grids on Earth, the aurorae such as the Northern Lights, and the plasma tails of comets that always point away from the sun.
Solar Wind Flow Pressure is something that is tracked daily by the Space Weather Prediction Center (SWPC) For example they display a nifty solar wind dashboard gauge on Space Weather Now that shows “dynamic pressure”:
Dynamic Pressure Dial:
Ranges from 0.1 to 100 nPa. The scale is log10 over the full range. If the density or speed data are missing, the arrow will not appear. The arrow will move to the location on the scale corresponding to the actual value of the latest 15 minute average of the Dynamic Pressure P of the solar wind. Dynamic Pressure is a function of speed and density.
David Archibald writes:
Robert Bateman’s graphic of the solar wind sent me in search of a longer time series. I found a longer one, and one that is a more accurate indication of the force that is pushing the galactic cosmic rays out from the inner planets of the solar system. It is the three month smoothed, 27 day average of the solar wind flow pressure. The data is from the Omniweb site.
The narrow downtrend channel that started in 2005 is quite evident. Before that it was trendless, and didn’t change with solar cycle amplitude. The volatility within the downtrend is much less than it was prior to 2005. Also evident is a big oscillation in 2004, which may be an artefact of a switch that changed the mode.
From this chart, solar activity is still falling until the downtrend channel is broken. As the solar wind takes a year to reach the heliopause, the Oulu neutron count will continue to rise for the next year. But just as the Earth’s atmosphere has shrunk, the heliopause will also be shrinking.
However this Archibald graph only shows a narrow slice of the entire data picture, Leif Svalgaard has an OMNI2 dataset that tracks back to 1963:
While we can indeed see the current downtrend since 1997, we have had periods before where the solar wind has been almost as low . Though NASA said last year “This is the weakest it’s been since we began monitoring solar wind almost 50 years ago.”.
There is an overall down trend since 1992, with a short plateau at the last solar max around year 2000-2004, followed by another downtrend starting about 2005.
In terms on the sun’s history (if it were compared to a day) we have about a microsecond worth of data out of that day on display above. So what conclusion, if any, can we draw from it? The only one I can see is it showing reduced solar activity, but nothing profound (in terms of the solar wind data we have) except that. We see a low period of similar amplitude around 1970, but it is noisier. The trend we’ve seen since 2005 is less noisy, which is inline with the quiet sun we have observed recently.
Let’s hope sol gets the magneto revved up again.
UPDATE: I had written to David Archibald, saying that “the broader data set to 1963 didn’t agree with your conclusions”, and he wrote back within about 15 minutes and provided a new graph:
Anthony, Agreed, and thankyou.
I went back to find the larger data set, as follows:
It is evident that the longer picture is more complicated. The correlation with solar minima and maxima is quite poor. Activity did not recover into Solar Cycle 23.
Yours sincerely,
David Archibald
So now we have all the makings of a good debate.
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From Wiki:
The solar wind is a stream of charged particles—a plasma—ejected from the upper atmosphere of the sun. It consists mostly of electrons and
The paragraph that starts with this sentence is repeated twice…
Regarding the UPDATE, Archibald again does cherry picking: omitting the low values [as low as today] before 1971, even though all the values are part of the same data set: http://omniweb.gsfc.nasa.gov/form/dx1.html
Leif – while I really appreciate reading your science input in many of the solar discussions that are held on this blog, I do find the personal attacks on Dave Archibald rather unprofessional and unneeded. Might I be so bold as to suggest that at least in public you debate the science only and not slur the man.
It’s the “noise” in the solar pressure I find fascinating to speculate on, the possibility of a rapid change, I mean. Is it possible for a burst of solar activity to ablate the upper atmosphere by “wrapping” up a pocket of atmosphere in a magnetic eddy and then that eddy being blown into space?
I had heard that some version of this was posited for Martian atmospheric (partial) depletion, but Mars has a very weak magnetic field so that theory may be more possible with Mars. Earth’s magnetic field would change things based on relative field strengths, and somebody would have to do the Math if the theory passed the conceptual phase.
@Ron de Haan (21:03:01) :
“So, a “quiet” Sun is when you would expect to find far more magnetic disturbances on the Sun, and more tectonic plate movement on the Earth.”
Seriously?
Plate tectonics is driven by density. Temperature and compositional density are the only things that matter to PT.
Folks, we’ve got some data and we’ve got some ideas, but so far nothing is making a lot of sense to me. Up to this point we are not far from this: Reindeer fart less when the FP is low. FP is now low. Less methane. Less warming. Earth cools.
Sorry about that but there is no eureka moment here.
Leif Svalgaard (20:55:58) :
The narrow downtrend channel that started in 2005 is quite evident. Before that it was trendless, and didn’t change with solar cycle amplitude.
“Count on Archibald to make unfounded claims based on cherry picked data. Here is the real record of spacecraft measured flow pressure from 1963 until today:” http://www.leif.org/research/Solar-Wind-Flow-Pressure.png
What unfounded claims? Your own graph confirms no trend associated with solar cycle. Spectators can compare
http://www.swpc.noaa.gov/Media/graphics/SolarCycle.gif
And you own graph also confirms flow pressure being in the longest lasting low event(<2) over the last ~3 years in 40 years, with a definite downtrend over the last 15.
We see a low period of similar amplitude around 1970, but it is noisier. The trend we’ve seen since 2005 is less noisy, which is inline with the quiet sun we have observed recently.
Sometime in the mid 1970s it snowed near Sacramento (Twice IIRC). Very out of character for the area. I don’t remember any snow since (though I moved out a decade or so later, snow in Sacramento area tends to make news.) From the Channel 10 (local TV) page:
” The last time there was an official accumulation of snow came on February 5, 1976, when two inches of snow fell over the capital city.”
Probably the same event.
I got to ride a bike through the snow then, so it made an impression… fairly slick and very cold toes (open toes – i.e. nothing covering them. Nobody was expecting snow, since it doesn’t snow there 😉
So if there is a 6 year lag… that would be snow in 2015 ?
Mark your calendar and let me know if I called it! (If it doesn’t snow then it was just a rampant speculation… If it does snow then I’m clearly understanding everything 😉
Archibald’s ‘narrow channel’ doesn’t surprise me too much, given the consistently low sunspot count since 2005.
Leif, it all looks biblical to me.
Tom in Texas (20:23:55) :
“2012 is zero”
oh well !!!
Darren Ferdinando (22:45:25) :
Might I be so bold as to suggest that at least in public you debate the science only and not slur the man.
I hope I was debating the science and not the man. The claims were unfounded and the graphs picked to back up the claims, first by only showing the last cycle, later by omitting the first cycle of the data with equally low values. I will object to anybody making such claims, not in particular David Archibald.
Glenn (22:58:13) :
What unfounded claims? Your own graph confirms no trend associated with solar cycle.
The solar cycle variation is clear and expected and observed since at least 1890. The latest cycle is unusual in that respect and deserves [and is getting] further study. In an earlier post, I speculated on what the cause might be.
The interesting point that arises from Leif’s graph is that when DP is at its lowest (1970 & now) the Sun is taking taking its greatly altered path around the SSB. Between those years the path is normal and the last time we had an altered path was the Dalton.
Anthony, in 2005 the Sun enters that altered path.
http://users.beagle.com.au/geoffsharp/carsten.jpg
re Voyager:
San Francisco, CA. – NASA’s Voyager 2 spacecraft has followed its twin Voyager 1 into the solar system’s final frontier, a vast region at the edge of our solar system where the solar wind runs up against the thin gas between the stars.
However, Voyager 2 took a different path, entering this region, called the heliosheath, on August 30, 2007. Because Voyager 2 crossed the heliosheath boundary, called the solar wind termination shock, about 10 billion miles away from Voyager 1 and almost a billion miles closer to the sun, it confirmed that our solar system is ” squashed” or ” dented”- that the bubble carved into interstellar space by the solar wind is not perfectly round. Where Voyager 2 made its crossing, the bubble is pushed in closer to the sun by the local interstellar magnetic field.
http://voyager.jpl.nasa.gov/
and an interesting paper at http://sd-www.jhuapl.edu/VOYAGER/manuscripts/outer_heliosphere_rlm.pdf
Leon Brozyna (22:15:59) :
To the point, what is the shape of the heliosphere. When I read, “The solar wind creates the Heliosphere, a vast bubble in the interstellar medium …,”
To first approximation it is a bubble with a stubby tail trailing the sun’ movement through the interstellar medium. Since the shape is determined by pressure balance between the solar wind and the interstellar medium any inhomogeneities in either will create ‘bumps’ on the boundary. Here http://swoops.lanl.gov/data.html you can see what the Ulysses spacecraft measured as it was going from pole to pole. The ‘momentum flux’ is the flow pressure. It is not quite a circle [or sphere], but also not far from it, perhaps with a waistline. It is interesting to note that the density is VERY asymmetrical as is the speed, but the momentum flux = (density * speed) * speed is much more spherical. The magnetic field is not important in shaping the heliosphere because the plasma flow energy dominates.
Leif Svalgaard (22:34:23) :
Pg 10 was an average of solar cycles.
Does anything interesting show up before 1963, as in another instance of what is going on now? By that, I mean if you took the density and multiplied it by the cycle average.
Leif Svalgaard (20:55:58) :
my simple explanation is that the polar fields are so weak that they have not been able to compress the solar wind down into a narrow equatorial belt, which with its higher density would give a higher FP.
Hi Leif,
not sure if all the graphs presented are 27 day average (one solar rotation), but could your hypothesis be tested by measuring how quickly the earth pass north and south of the heliospheric current sheet? i.e. measure the angle and deduce the amplitude of the ‘folding’ in the HCS to get a handle on the effect of the polar field on the lateral spread of the solar wind.
another interesting link. It appears that Voyager has been taking solar wind speed, density, temp and pressure readings since its launch. They plotted it out…
http://web.mit.edu/afs/athena/org/s/space/www/voyager/voyager_data/voyager_data.html
Lubos Motl on CERN : CLOUD (cosmic rays and clouds)
http://motls.blogspot.com/2009/06/cern-cloud-on-cloud-number-nine.html
rbateman (23:43:11) :
Pg 10 was an average of solar cycles.
Does anything interesting show up before 1963, as in another instance of what is going on now? By that, I mean if you took the density and multiplied it by the cycle average.
No, the situation now has not been seen since 1890. Here is the average solar variation of density n, magnetic field B, and speed V:
http://www.leif.org/research/Space-Climate-n-B-V-Flow.png
The right-hand panel shows the flow pressure calculated as n*V^2
In both panels, the red curves are for direct observations since 1965 [1963-1964 has very little data], while the blue curves are calculated over 11 cycles since 1890 from the geomagnetic proxies. They usually agree rather well and makes the current low values at minimum special, since in all the other ones there is a flow pressure maximum on the approach to minimum.
tallbloke (23:52:31) :
your hypothesis be tested by measuring how quickly the earth pass north and south of the heliospheric current sheet?
The HCS is VERY thin and sweeps past the Earth in minutes every week or so, but presumably you mean the size of the ‘warps’ in the HCS. Here is a measure of that since 1976: http://wso.stanford.edu/gifs/Tilts.gif
The size is in degrees, meaning the latitude a spacecraft would have to have to be totally ‘above’ or ‘below’ the HCS. You can see that that latitude is larger for the current cycle, thus meaning a ‘thicker’ region wherein the HCS sweeps.
It is very likely that my introductory statement has an error in fact. It seems that the solar wind plasma flow (and I can rely upon Dr Svalgaard to correct me if I am wrong) doesn’t have much to do with the GCR flux, which is best anti-correlated with the IMF.
However, Dr Svalgaard states that it is strange that the solar wind flow pressure is declining into solar minimum instead of rising, so the decline I have plotted up is doubly significant.
layne Blanchard (21:43:27) :
Ron De Haan,
Are you suggesting the tectonic plate activity suggests gravitational forces are possibly the reason for the Sun’s activity?
and
Leif Svalgaard (21:58:44) :
Ron de Haan (21:03:01) :
So, a “quiet” Sun is when you would expect to find far more magnetic disturbances on the Sun, and more tectonic plate movement on the Earth.
We have direct measurement of solar magnetic field and disturbances for a century and indirect [but very good] indications of these thing another century back and the above premise is simply not what is observed, so the implication wouldn’t follow. [although curiously in symbolic logic any implication from a false premise is true: http://en.wikipedia.org/wiki/Truth_table#Logical_implication ]
and
Benjamin P. (22:51:09) :
@Ron de Haan (21:03:01) :
“So, a “quiet” Sun is when you would expect to find far more magnetic disturbances on the Sun, and more tectonic plate movement on the Earth.”
Seriously?
Plate tectonics is driven by density. Temperature and compositional density are the only things that matter to PT.
I did not write the article but thanks for the comments.
I have copied the article directly from the link and published the link with it.
I think the remarks come from Piers Corbijn.
The question that puzzles me is why does the press eagerly print every absurd claim that the believers offer, while at the same time mostly ignoring rational and undeniable evidence that is presented by us [snip (skeptics)]. Can the press no longer be bothered to check, or is it that the doomsday scenario is more attractive and sells newspapers or adverts. We know that, at climate conferences, an increasing number of scientists are declaring that AGW is a fraud but I have yet to actually read this in any newspaper or hear it on television. What is needed is an onslaught, a campaign, to get the message to the public. When anybody tells we the world is warming, I always ask them how much Co2 is in the atmosphere. You would be amazed at the ignorance.
Very interesting graphs there… Has the Ap Index plot been updated for May 2009? Are the values still around 2-4?
Solar wind has been quite weak this year too.
The weather here is miserable; snow in the Free State, Berg, and Lesotho; heavy rain in the north and very cold everywhere except the southern Cape; the media has tried to blame it on “global warming” but the public ain’t buying it.
I’m sorry if this has been asked before, but is there any chance of a correlation between solar activity and volcanic activity?
Could we have these solar flux graph overlaid with the AP index and the Sunspot count, so we can compare the various datasets?
If we were to propose an 8-year lag between solar flux and resulting global temperatures, would Svalgaard’s solar flux graph not equate very well with the global temperature graph??