Sunspots, size? weather? (APOD 06 Feb 2008)

[neufer]

http://apod.nasa.gov/apod/ap080206.html

I gave a talk at the American Geophysical Union about a year ago on how Sunspots might affect the earth's weather. While the sunspot cycle only modulates the Sun's visible output by about 0.1% it modulates the UV output by a whooping 10%. This excess 10% heats up the earth's Stratopause in the subtropical summer hemisphere just enough that the entire Stratosphere catastrophically overturns in a sort of giant Hadley cell (i.e., Brewer-Dobson circulation) resulting in winter hemisphere polar night Stratosphere sinking and, thereby, adiabatically heating. This (sunspot enhanced) Sudden Stratospheric Warming in turn has some marginal subtle affects on winter tropospheric weather that are still being examined.

http://en.wikipedia.org/wiki/Image:Nimb ... lation.jpg

[emc]

What are some of the key earth weather effects from the 11 year sun cycle? Are the effects consistent over longer periods or are there other key fluctuations in different durations... say some harmonic in time like 22 years or 1100 (if there is any pertinant info from that long ago)? I am curious how much we (we meaning other than me) know about sun cycles.

[henk21cm]

What are some of the key earth weather effects from the 11 year sun cycle?

Well, next statement has a limited validity:

There seems to be a slight preference for the Azore high to extend or drift to more northern latitudes, when the sun is at his maximum activity.

"So i was told", in the sixties. The reason for this drift was unknown.A few years ago i downloaded the key meteorological data of "De Bilt" (station 260) of the last century and performed a Fourier analysis on the daily averaged air pressure. The resulting spectrum did not reveal a significant peak around 11 years of multiples of 11 years. "Just noise".

More negative effects: The occurence of two extremely hot summers (1947 and 1959) around the solar maximum seems to be accidental, since the summers 1970/1971 were not outstanding.

The little ice age, around 1600 is generally linked to a minimum in solar activity.

[neufer]

What are some of the key earth weather effects from the 11 year sun cycle? Are the effects consistent over longer periods or are there other key fluctuations in different durations... say some harmonic in time like 22 years or 1100 (if there is any pertinant info from that long ago)? I am curious how much we (we meaning other than me) know about sun cycles.

When the winter night polar regions are LESS cold they are less able to hold a strong stable band of zonal westerly wind around them. This leads to large meanders of the jet stream with wild variable winter weather in the mid latitudes. I suspect that is precisely what is going on currently with this year's winter weather due to the record melting of the Arctic ice sheet recently.

Strong Stratospheric Warmings which extend down to warm the upper Arctic troposphere should have a similar (although somewhat weaker) result in inducing large meanders of the jet stream with wild variable winter weather in the mid latitudes.

Part of the problem with recognizing this particular effect of sunspot maximum (or global warming) on winter weather IMO has been the difficulty in quantifying wild variable winter weather on a global basis.

I can't speak about the solar 22 year cycle and it's possible climate effects (on droughts for instance) because the possible physical mechanism alludes me.

[emc]

Have there been any correlations in weather relative to the 9-14 yr fluctuations in the solar cycle?

[neufer]

What are some of the key earth weather effects from the 11 year sun cycle?

Well, next statement has a limited validity:

There seems to be a slight preference for the Azore high to extend or drift to more northern latitudes, when the sun is at his maximum activity.

"So i was told", in the sixties. The reason for this drift was unknown.A few years ago i downloaded the key meteorological data of "De Bilt" (station 260) of the last century and performed a Fourier analysis on the daily averaged air pressure. The resulting spectrum did not reveal a significant peak around 11 years of multiples of 11 years. "Just noise".

More negative effects: The occurence of two extremely hot summers (1947 and 1959) around the solar maximum seems to be accidental, since the summers 1970/1971 were not outstanding.

The little ice age, around 1600 is generally linked to a minimum in solar activity.

There has been some difficulty in the past in even recognizing the effect of the 11 year sunspot cycle on Polar Stratospheric Warming itself...that is until folks (finally) started also concentrating on the QBO (Quasi-Biennial Oscillation) cycle in Equatorial Stratospheric Winds [particularly on the Westerly (super rotation) phase]:

• The Global Signal of the 11-year Sunspot Cycle in the Stratosphere:
  Differences between Solar Maxima and Minima (Labitzke, 2001)
  
  <<During the west phase of the QBO, the [solar/stratospheric warming] correlations are positive and the height differences large, up to +450 geopot.m., over the Arctic in January/February, due to the fact that in this phase of the QBO major stratospheric warmings tend to take place during solar maxima. These strong stratospheric warmings over the Arctic are connected with widespread downward motion over the Arctic and middle high latitudes.>>

Only when this (QBO modulated) 11-year sunspot effect on Arctic stratospheric warmings becomes strongly established (and well understood) can one seriously consider the secondary winter time tropospheric weather sunspot effect.

Whether or not the 300 year Little Ice Age (1550 to 1850) and the MUCH shorter 70 year Maunder sunspot minimum (1645 to 1715) are related (and/or have anything to do with the above) is debatable IMO. One can argue that our recovery from the Little Ice Age is almost solely due to (coal/gasoline burning) global warming (and, possibly, that our entry into the Little Ice Age was almost solely due to human agricultural burning).

[craterchains]

What about the amount of H2O now showing up in our upper atmosphere? That should also have a pronounced effect on overall warming and could be beneficial, if looked upon from another view point.

[neufer]

Have there been any correlations in weather relative to the 9-14 yr fluctuations in the solar cycle?

You are referring, to the 9-14 yr fluctuations in the length of solar cycle.

Certainly the length of the present solar cycle is more like 10 years whereas back in the Little Ice Age days it was more like 12 years and it is certainly worth investigating whether the current shorter solar cycle is indicative of a hotter sun but that's about all I can say.

[iamlucky13]

I suspect that is precisely what is going on currently with this year's winter weather due to the record melting of the Arctic ice sheet recently.

So this increase in circulation is due to UV heating during the solar maximum. We are in the solar minimum right now, however, correct?

While the sunspot cycle only modulates the Sun's visible output by about 0.1% it modulates the UV output by a whooping 10%.

Does the visible and infrared output drop during the peaks resulting in this minimal shift in total output at the same time as a 10% increase in UV output, or is UV only ~1% of the output to begin with?

Very interesting information. I'm curious where your involvement in this comes from.

[neufer]

What about the amount of H2O now showing up in our upper atmosphere? That should also have a pronounced effect on overall warming and could be beneficial, if looked upon from another view point.

A good deal of very long wavelength (20-100 micron) infrared radiation back into space is modulated by upper tropospheric H2O. The current warm Arctic is generate large meanders in the jet stream which results in a sinking and drying of the troposphere which, in turn, leads to more 20-100 micron radiation back into space. It has been suggested that this enhanced radiation will act a negative feedback to global warming (at least in the short term).

The recent Arkansas tornado was caused by a strong trough that also caused considerable sinking a drying of the upper troposphere and, hence, stronger (red & black) infrared outgoing radiation as observed by a GOES water vapor channel:

The bright (red & black) infrared outgoing radiation here at 6.5 microns is representative of bright 20-100 micron infrared outgoing radiation(which is somewhat harder to directly measure from space).

[neufer]

I suspect that is precisely what is going on currently with this year's winter weather due to the record melting of the Arctic ice sheet recently.

So this increase in circulation is due to UV heating during the solar maximum. We are in the solar minimum right now, however, correct?

The last couple of years we have been in solar minimum and thus the Stratospheric polar regions have been more quiescent. That probably explains why 2006 had one of the largest and longest lived Antarctic ozone holes in spite of less CFC's in the atmosphere. The Stratosphere may not be as dynamically favorable for a large stable Antarctic ozone hole again until the 2016 sunspot minimum and by that time CFC's will be down considerably.

While the sunspot cycle only modulates the Sun's visible output by about 0.1% it modulates the UV output by a whooping 10%.

Does the visible and infrared output drop during the peaks resulting in this minimal shift in total output at the same time as a 10% increase in UV output, or is UV only ~1% of the output to begin with?

Visible darkening due to sunspots is more than counterbalanced by active bright features.
The ~0.1% variation corresponds the total solar radiation variation at the earth's surface
which essentially means visible radiation (which peaks at solar max):

• http://sdo.gsfc.nasa.gov/images/site/su ... si_web.png
  http://science.nasa.gov/headlines/image ... ectrum.htm
  
  <<At wavelengths shorter than about 300 nm, there is a relatively large variation in the Sun's extreme UV and x-ray output (greater than 1%), but the Earth's atmosphere is nearly opaque at those wavelengths. For Earth-dwelling beach-goers there is no significant difference between Solar Max and solar minimum.>>

Very interesting information. I'm curious where your involvement in this comes from.

I just retired from NOAA/NESDIS last year after 36 years.

[tom2688]

just curious as to the size of the sun spot as compared to earth??? tom

[auroradude]

The area is 10 one-millionths of the surface area of the visible sun - whatever that translates into. I believe it is rather tiny for a sunspot.

I have not found anything on weather this spot, 10982 actually belongs to the new cycle 24. It is only at a latitude of 9 degrees south and may belong to the old cycle 23. Sunspots of a new cycle appear at high latitudes and migrate towards the equater as the cycle progresses.
Sunspot 10981 was confirmed as the first sunspot of cycle 24 back in January 2008 around the 4th. It had reversed magnetic fields and was at latitude 30 degrees north. Both indicators that it belonged to the new cycle.
There is no definate dividing line between cycles and they will overlap for several months.

[neufer]

I have not found anything on weather this spot, 10982 actually belongs to the new cycle 24. It is only at a latitude of 9 degrees south and may belong to the old cycle 23. Sunspots of a new cycle appear at high latitudes and migrate towards the equater as the cycle progresses.
Sunspot 10981 was confirmed as the first sunspot of cycle 24 back in January 2008 around the 4th. It had reversed magnetic fields and was at latitude 30 degrees north. Both indicators that it belonged to the new cycle.

Surely http://apod.nasa.gov/apod/ap080206.html
is, in fact, Sunspot 10981 at 27 degrees North:

http://www.noaanews.noaa.gov/stories200 ... nspot.html

[auroradude]

The info on today's image says that it was taken on January 31st but there is no mention of orientation. On the 31st 10982 was 40 degrees east that would make the orientation of east at the top of this image if it is indeed 10982.

[auroradude]

Thank you Art for the expertise.
I have a question about one event in particular and a generalization of such events: Back in late October of 2003 we experienced the impact of CME's related to two huge solar flares. I had read that these actually stripped off some of the Earth's outer atmosphere and that it took months to fully recover. Was there a noticable or measurable difference in the amount of penetration of short wavelenght radiation or was it all-in-all insignificant?

[iamlucky13]

http://science.nasa.gov/headlines/image ... ectrum.htm

<<At wavelengths shorter than about 300 nm, there is a relatively large variation in the Sun's extreme UV and x-ray output (greater than 1%), but the Earth's atmosphere is nearly opaque at those wavelengths. For Earth-dwelling beach-goers there is no significant difference between Solar Max and solar minimum.>>

Aha! That's exactly what I was asking. That's a really interesting and information-dense graph (although it took me a while to figure out what it was really showing).

I just retired from NOAA/NESDIS last year after 36 years.

Congratulations on your retirement.

[auroradude]

Yes, that certainly answers the question of short wavelength radiation at the surface but I also wonder if upper regins are affected such as the mesosphere and possibly polar mesospheric clouds (noctiluscent clouds) or if there would be increased heating of the upper stratosphere by UV radiation and any possible effects on the stratosperic ozone.

[neufer]

I just retired from NOAA/NESDIS last year after 36 years.

Congratulations on your retirement.

Thanks, iamlucky13.

[neufer]

Yes, that certainly answers the question of short wavelength radiation at the surface but I also wonder if upper regions are affected such as the mesosphere and possibly polar mesospheric clouds (noctiluscent clouds) or if there would be increased heating of the upper stratosphere by UV radiation and any possible effects on the stratosperic ozone.

I'm sure that all of the above are affected by the solar sunspot cycle but it is ONLY the stratosphere of the winter hemisphere that is in a unstable dynamic state such that it permits for the amplification of the very weak solar signal.

[neufer]

Thank you Art for the expertise.
I have a question about one event in particular and a generalization of such events: Back in late October of 2003 we experienced the impact of CME's related to two huge solar flares. I had read that these actually stripped off some of the Earth's outer atmosphere and that it took months to fully recover. Was there a noticeable or measurable difference in the amount of penetration of short wavelength radiation or was it all-in-all insignificant?

My "expertise" , so to speak, stops at the warm (ozone heated) Stratopause at 45 km. You are talking about effects in the thermosphere, ionosphere, and exosphere:
http://en.wikipedia.org/wiki/Image:Atmo ... sphere.svg

Disruptions in radio transmission and pretty aurora to be sure:
http://antwrp.gsfc.nasa.gov/apod/ap031104.html
http://antwrp.gsfc.nasa.gov/apod/ap031030.html
http://antwrp.gsfc.nasa.gov/apod/ap031029.html

I was talking to a frustrated scientist at an AGU meeting who was studying the affects of flares on the upper atmosphere with satellites. The problem was that his attempts to monitor these events was thwarted because the folks in charge of the satellites had to turn them off to protect them from the flare.

[auroradude]

Thanks for that.
I can relate to the frustration of not being able do the science at the very time that it would be so much desired. It would be inconceivable that I would have to switch off my cameras during such an event.

http://www.spacew.com/gallery/image001984.html

[iamlucky13]

http://science.nasa.gov/headlines/image ... ectrum.htm

Returning to this graph simply because I find it very fascinating, I find a few things particularly interesting about it. We already know that atmosphere is nearly transparent to visible light, which is probably part of the reason we evolved to see in this wavelength range. At the same time, it's also the peak wavelength of solar output, a futher convenience for us. What I was surprised to see, is that it also is the most stable component of the solar output, with almost the entire range, as neufer noted, maintaining a constant output throughout the solar cycle.

I also was mildly surprised how closely most of the output curve mimicks the black body curve. It's always satisfying to see theoretical results upheld in the real data.

[neufer]

http://science.nasa.gov/headlines/image ... ectrum.htm

Returning to this graph simply because I find it very fascinating, I find a few things particularly interesting about it. We already know that atmosphere is nearly transparent to visible light, which is probably part of the reason we evolved to see in this wavelength range. At the same time, it's also the peak wavelength of solar output, a futher convenience for us.

On the other hand, one would assume (for both the same reasons) that earth plants would have evolved to make use of all that strong yellow/green light that is available at the surface of the earth; and yet leaves & grass are green because that is precisely the frequency that the plants reject...go figure

[lankytom]

I would like to refer you to the subject of the "Maunder Minimum." That was a period from around 1645 - 1715 when sunspots were at a minimum or even absent and a mini ice age descended on Europe. I'm not sure of the mechanism. I saw a discussion relating to more heavy particles in the solar wind when sunspots are numerous. The heavier particles interact with or block more cosmic rays, reducing cloud cover. With minimal sunspots the solar wind apparently interacts less with cosmic rays, cloud cover increases, and cooler, colder weather results. I note that the current solar cycle has started out with greatly reduced sunspots, while Fairbanks Alaska has just experienced a cold snap period they haven't had in 10 years or so and a longer cold snap for many more years. Some scientists think we may be about to experience some global COOLING rather than global warming. We may have a great opportunity to track weather again with sunspots.