Sunspots, how accurate is the count?

I’ve come across a very good site here.  In it, there is some serious discussion regarding the calculation of the Sunspot Number, and it’s deviation from the original Wolf number.  If you have the opportunity have a look, a fascinating site, well presented.

One very nicely organised piece is on the “Layman’s Sunspot Count”, trying to correct the two counts taken as being the official view, and  correcting them by removing specks that, in previous times, would not have been seen even with telescopes

Sunpots starting in earnest??

It looks as though the sun is finally waking, since the start of 2010 (this is written on Feb 11th), we have had a grand total of 2 days without a spot being recorded on the face of the sun, this is a distinct improvement on 2009 where there were 76% of days throughout the year without any spots at all.

Of more interest however is the sunspot number, this is still consistantly below the number forecasted by NASA. In fact Solar Cycle 24 is still shaping up to be one of the quietest cycles of modern times, and that’s if you take the definition of modern back 100 years. Cysle 23 was one of the longest recorded, as 13.4 years, while cycle 24 looks as though it’s going to be a low powered cycle that may also be a long cycle. Many radio amateurs will be hoping for a bit more than what we’ve seen so far, as the 10M band has, as far as I’m aware, not been open since the end of cycle 23

Sunspots, or lack of them

We may, if we are lucky see a rare thing in the next few days, it is just possible that a sunspot may appear as the sun rotates round, the SOHO Behind satellite seems to be recording activity at high latitude, which should indicate a cycle 24 spot.  We are now at day 13 of the current spotless run, we had a brief 4 day spotted run before this current spell, but before that we had a full 52 days without any spots at all.

This year to date we have had 206 spotless days, that’s 80% of the days this year (not that the sun knows what one of our years is), with a total of 717 spotless days since 2004. The average number of spotless days since records began is 485 days, so we are climbing the listings for quiet cycles.

There have been various comments about the strength of this cycle with much criticism of Hathaway at NASA.  What has happened is that his forecast is early, as he had forecasted a much quieter cycle 25 rather than 24.  The last 3 cycles, 21, 22 and 23 were strong and short, although 23 was weaker than 22 and 22 was weaker than the big 21, but now the sun has switched off, at least as far as sunspots are concerned.  There was a period earlier in the year where it looked as though this cycle was starting to take off, but that lasted just over 2 months and the slumber resumed.

What does this do to the climate? Records show that during the Dalton minimum and the earlier Maunder Minimum parts of Western Europe had shorter growing seasons and much colder winters. Parts of the Northern American Plains In the US and Canada were also substantially cooler.  This year, many US Mid West States were substantially cooler than the norm.  Parts of the UK have had a washout of a summer, with a jetstream that has been consistently further south than is normal for the time of year.   Viewing the way the climate has behaved in both the Northern and Southern Hemispheres this year, it seems that the warmer weather from sub tropical zones seems to be drawn closer to the equator, with the colder polar zones expanding, from the poles, giving a small net cooling of the whole planet, but with large regional variations.

Solar UV and Black Body Radiation

Data provided on websites over the last few weeks seem to indicate that, as the Sun takes a rest during solar Cycle 24, UV Radiation has dropped by about 6%.  I think this 6% is quite a drop, especially if you look and see that Total Solar Irradiance (TSI) only varies by between 0.05 to 0.1% over a Solar Cycle.  This variation in TSI is thought to be too insignificant to affect climate, but what of the UV Decrease?

It’s well known that the majority of UVB and almost all UVC Radiation is absorbed by the upper atmosphere, mainly by ozone.  But this radiation is, after absorption, re-emitted as black body radiation.  Black body radiation is taken to be emitted in any direction, which means at least 50% is passed towards space, where it may be absorbed and re-emitted again.

Associated with this drop in UV is a decrease in the diameter of the atmosphere.  NASA have said that satellites are experiencing less atmospheric drag when in low orbit (low orbit being between 120 and 200 Km above the surface).  This means that there is less atmosphere, at the edges, to intercept UV.

So what if Carbon Dioxide is not the primary driver of climate variations?  Perhaps UV plays a much larger role than previously thought. Perhaps, with a suitable lag due to the heatsink that is the oceans, we will see a much larger drop in Global temperature than is currently expected.

If you have any reliable data concerning the absorption and re-emission of UV in the upper atmosphere, I would appreciate seeing it

The quiet sun (continued)

NASA’s position seems to be changing. A couple of days ago they put out this about the Solar minimum. There is a very healthy discussion of this on wattsupwiththat , but I’d like to add a few points of my own, expanding on points from within the press release.

I suppose the first point is that the report is authored by someone other than NASA’s usual expert trotted out on these occasions, David Hathaway.  Instead it’s authored by Dr Tony Phillips, who looks after the site updated daily by NASA.  Hathaway is quoted, butjust saying that “It’s the quietest sun for almost a century”  Looking at a previous presentation by Hathaway, there was an expectation, in early 2007, that the next cycle, cycle 25, would be weaker than 24, see this presentation powerpoint presentation. In fact he points out within the same presentation that the methodology used by another US Scientist, Dikpati, may be flawed.  In fact, reading between lines, to me it seems that the presentation, taken as a whole points to a lower Cycle24 than originally indicated.

Secondly, of the points made, in order of importance, the drop in extreme UV of 5% means that the amount of heat received, and aborbed by the planet stands out.  UV radiation is almost completely absorbed by the atmosphere, and is turned into heat, a drop of 5% in the extreme UV range doesn’t mean that the temperature of the planet will drop by 5%, but probably does mean that there will be a cooling trend of about 1.25 to 2.00 degrees across the planet.  There will still be individual variations where places may get warmer, but the overall trend is down.

Solar Wind pressure is also at a 50 year low, this allows more Galactic Cosmic Rays to hit our lower atmosphere.  That produces more clouds, more clouds mean a higher albedo, more sunlight is reflected, and until the sun picks up, we have the possibility of a viscious circle, with Cold having a positive feedback loop established.

Hathaway’s comment “Since the Space Age began in the 1950s, solar activity has been generally high,” notes Hathaway. “Five of the ten most intense solar cycles on record have occurred in the last 50 years. We’re just not used to this kind of deep calm.” is most instructive.  The whole Global warming hype has been with us for about half of that time.  In other data, a drop of  0.1 C can be seen at each Solar Minimum, but the minima of the last few cycleshave been very short before the sun ramped back up with lots of spots, yet even in those minima we see a global drop in temperature, so where do we go with a long minimum?  Just hope it isn’t a Dalton or Maunder length of time or things could get tricky.

Further updates later