[Dave K]

Quote

Recent cold winters that brought chaos to the UK and other places in northern Europe may have their roots in the Sun's varying ultraviolet emissions.

The latest satellite data shows the UV output is far more changeable than scientists had previously thought.

A UK scientific team now shows in Nature Geoscience journal how these changes lead to warmer winters in some places and colder winters in others.

http://www.bbc.co.uk...onment-15199065

[ldavidcooke]

Hey BDG,

This is a question that the experts may be looking for an answer for a while. The problem as I see it is the issue of what is the cause of the high levels of UV in some areas and low levels in others. To go further can we see evidence in the warming of the ocean.

Recently on RealClimate we were discussing the inflow of energy warming the ocean depths. According to the TOA/Trition buoy data set though there may be some increase of Sea Surface Temperatures (SSTs). And where the ARGO buoy data set suggests there appears to be increased warmth penetration (See NOAA NODC Ocean Heat Content), the areas in question were heavily shaded by Low Pressures (according to NOAA, NCDC NCEP SRRS data sets for 2010 JFM at 250mb, 500mb and 850mb). At the same time in areas of Blocking High Pressures there were no Ocean Heat Content depth anomalies. This would appear to suggest that the UV penetration is not warming the ocean much other then the SSTs near large Clear Sky High Pressure regions, as indicated by high Sea Surface Salinity (SSS)data.

Of course I cannot bring this up on RC; but, the point is that there appears to be additional insolation causing high levels of evaporation and residual salinity. It is also clear that the regions of high Salinity are under Clear Sky High Pressure influences. The biggest difference appears to be that much of the new deviations in SSTs are happening in the higher latitudes (above 45 deg. N). The probability that the additional heating is more due to long resident High pressures is much higher then suggesting the greater cause is the increased UV. Though the increased UV is occurring it is more likely isolated to the upper troposphere where it would react with water vapor reducing condensation and cloud formation.

The idea of reduced clouds due to UV is not currently supported by any papers I have seen, though last year a paper was published that suggested that Global Warming was responsible for reduced clouds. I think when the data is reviewed it will become more clear that there is a cause and effect going on that deserves more research.

As to the source of the colder waters, and possible winters I believe the secret can be found in the Blocking High that took up residence SW of Iceland last year. It clearly was pumping tropical warmth into the Arctic region enhancing the sea ice melt this past Summer. In the meantime the cold Arctic vortex split to form two circulations a weak one over the NA continent and a strong one over the Eur-Asian continent. This also changed the circulation in the northern waters which pulled the Polar cold further south then normal.

This deviation in the Northern Jet Stream has been suggested to be an artifact of Global Warming by one group and the La Nina by another group. Personally I beleive it to be an artifact of the high level of aerosols that were injected into the polar region last year enhancing the cooling of the upper air (above 300mb) increasing long resident Blocking Highs in the Higher latitudes and Cut-Off Lows at the temperate latitudes.

Looking at Asia last year it was clear that the Jet Stream had dipped to below 30 deg. N causing a series of Lows to orbit between the Northern Central Continent region, to the South China Sea, to Northern Siberia and back again, twice. It was this long resident Low characteristic that makes me doubt the ARGO data 50-500 meter warming that has been documented for the China Sea and Newfoundland regions last year.

So is the UV playing a part, yes, in the long term it is as far as high altitude or vertical temperature profiles. however, it is also clear that most of the UV variability has to be due to high levels of upper air cooling, increasing the break down of Ozone by the Chlorine ions there. As we know the UV variation is not increasing above historic measures; it is falling to very low levels instead. Hence, UV as a driver in this case is unlikely, it is symptomatic of other phenomena IMHO.

[John Mason]

Just been listening to an interview on the Today Programme about this. Quite interesting that low UV input over a deep Minimum, when fed into a climate model, recreates a cold NW Europe and warm Arctic, which is pretty much the pattern of recent winters. With a more active Sun in recent months, are we to expect greater zonality this winter or is there a lag in the process?

The author interviewed made the point that this is about regional variations over short-term cycles and was nothing to do with AGW, although I'm not sure that's how sections of the Blogosphere will react!

Cheers - John

[snow hope]

It is worth noting that this research and the measurements from the Spectral Irradiance Monitor (SIM) over the last 7 or 8 years, "suggests the UV variation is about five times larger than had been inferred from previous observations." This is a very large variation and is bound to affect climate models that had not accounted for this variable correctly.

As I am forever saying we under-estimate the impact of the Sun upon our climate, this is further proof of that fact.

Ultra-violet radiation is simply a shorter wave-length of light (than visible light) hitting the planet. Although the majority is absorbed by the Ozone layer, a signifcant amount reaches the surface as can be vouched by anybody who has suffered sunburn from sitting in the sun too long!

[Andy Mayhew]

Quote

UV is absorbed in the stratosphere, the upper atmosphere, by ozone. So in the quiet bit of the solar cycle, when there is less UV to absorb, the stratosphere is relatively cooler.

Or, indeed, when there is less ozone to absorb the UV

Cause or effect? Or both?

http://www.bbc.co.uk...onment-15105747

[PK2]

Andy Mayhew, on 10 October 2011 - 12:37, said:

Or, indeed, when there is less ozone to absorb the UV

Cause or effect? Or both?

http://www.bbc.co.uk...onment-15105747

both presumably since the measurements referred to "Nature" are based on Satellites and hence (presumably) above the ozone layer. Might be wrong though ....

[PK2]

Short of buying a copy of Nature I guess this is our best chance of reading the paper undiluted by any (potential) journalistic spin

[snow hope]

Thanks for the link Peter.

I must admit this statement takes my breath away, "Joanna Haigh, Professor of Atmospheric Physics at Imperial College London, said: "Compared with the effect of man-made emissions over the last century, solar variations still have a very minor effect on long-term global climate trends, but this study shows they may have a detectable influence on winter climate."

I must be a lot stupider than I thought I was. I would really like to have a chat/discussion with Prof. Joanna Haigh to understand why she holds that view point.

Intuitively I would have thought that the solar variations of our local star, would be of much more significance than man-made emissions, but it would appear that man-made emissions must be much higher than I have heretofore realised.

[ldavidcooke]

Hey Michael,

The difference is in the incoming radiative energy at the earths surface. GHGs likely are responsible for the downwelling of roughly 1.85 watts / m^2 of IR 24 hours/day where solar variation at the same detection point is responsible for roughly 0.54 watts/m^2 every 11 years. The solar variation is full spectrum, having higher energy photons; however, the narrowness of the UV band actually balances out the broader IR band as to total energy potential. Meaning that GHGs offer 325% the energy of solar variations over the last 44 years and 1100% more often.

Even so, the GHG contribution is only 0.5% of the distributed solar input (7x24, 365 days). At best looking at global influences, the addition seems small; however, if you add in several other man made influences, the amount of energy availible to push natural variation far enough to upset the apple cart is present.

Removing GHG emissions will not overcome other man made influences; however, they are potentially the most important. Not the 5 Gt of Carbon from today; but, the potential 20Gt of Carbon by 2050. Though if we look at the historic peaks since 4 limbed life crawled out of the sea, the maximum heating that Carbon could contribute to the average global temperature is roughly 7deg. C and 14deg.C at the poles. (Added temperature, not absolute.) Though you also have to keep in mind there is not enough recoverable Carbon to exceed 1/2 of those values today. Finally, remember that the man made contributions are not the source of global warming, they push the natural systems to patterns that cause warmer surface conditions.

I will stop there as this is likely more then would be appropriate for a chat; but, maybe a good starting point for a couple chating threads where we can examine the differences in understanding many have when we discuss this issue.

As a final note, consider that for definitive values of natural changes, they are the best guess based on what Science is aware of today. Tomorrow may offer different insights, the hope is we can find a way to offer future generations similar environmental experiences as to what we grew up with, (Camping, Fishing, Hiking, Canoeing, Sailing, Skiing, Sleding, Gardening, Stargazing, Storm Chasing....).

[John Mason]

Michael,

Following on from David's post, here is an interesting piece in the National Geographic about the last high-carbon spike:

http://ngm.nationalg...rth/kunzig-text

Cheers - John

[PK2]

snow hope, on 10 October 2011 - 21:51, said:

Thanks for the link Peter.

I must admit this statement takes my breath away, "Joanna Haigh, Professor of Atmospheric Physics at Imperial College London, said: "Compared with the effect of man-made emissions over the last century, solar variations still have a very minor effect on long-term global climate trends, but this study shows they may have a detectable influence on winter climate."

I must be a lot stupider than I thought I was. I would really like to have a chat/discussion with Prof. Joanna Haigh to understand why she holds that view point.

Intuitively I would have thought that the solar variations of our local star, would be of much more significance than man-made emissions, but it would appear that man-made emissions must be much higher than I have heretofore realised.

at least in part the difference could be that the changes due to UV are thought to have a mostly regional effect. Hence they don't change the globally averaged temperature very much although they may make more difference in the UK. Also it depends on the magnitude of the variations in each case for clearly, in extremis, there's no amount of GHG heating that could compensate for the sun "turning off". She's only talking about the last century during which time there might not have been a great variation in the solar activity compared to, for example, the maunder minimum.

[Sunspot]

Is the Sunspot Cycle About to Stop?

http://www.skyandtel.../123844859.html
Original Press Release: http://www.boulder.s...cle_release.txt

Among the 320 solar physicists who have gathered for a conference in Las Cruces, New Mexico, word is buzzing about a claim that the 11-year solar-activity cycle, which some of them have spent their lives studying, may be on the verge of a drastic change.

At the meeting of the American Astronomical Society's Solar Physics Division, four scientists affiliated with the National Solar Observatory have posted three papers showing separate evidence that the solar cycle may be about to flatten right out.