New paper finds solar UV-B output is correlated to global mean temperature

Map of correlations suggest it may be affecting biomass and planetary albedo.

From the Hockey Schtick:

A paper published today in Methods in Ecology and Evolution describes a new satellite dataset of solar UV-B radiation for use in ecological studies. According to the authors, “UV-B surfaces were correlated with global mean temperature and annual mean radiation data, but exhibited variable spatial associations across the globe.” The finding is notable, since climate scientists dismiss the role of the Sun in climate change by only looking at the tiny 0.1% variations in total solar irradiance [TSI] over solar cycles, ignoring the large variations in solar UV of up to 100% over solar cycles, and which according to this paper, correlates to global mean temperature. Thus, the role of the Sun and solar amplification mechanisms on climate is only at the earliest stages of understanding.

In the supplemental information (SI) I found this correlation map, which was telling for me. Note the red of highest correlation – mostly in the tropics. This suggests to me that UVB is playing a role with ocean biomass, possibly modulating algae/plankton, which in turn changes the albedo, and absorption of other solar wavelengths into the oceans (which then affects nearby land-mass temperature).

UVB_to Temperature-quadmap1

The authors write: Finally, we mapped the four types of local spatial association for each pair of compared variables to show how the strength and type of spatial association vary geographically. Areas with non-significant relationship or negative (inverse) spatial association (Low-High, High-Low clusters) indicate locations where our glUV data provide new information (variability) that is not captured by considered existing climate variables. Below is an example of a LISA map for the above mentioned comparison of annual UV-B radiation versus annual temperature (Figure 4a in the manuscript).

Here is the press release:

Researchers at the Helmholtz Centre for Environmental Research (UFZ) have processed existing data on global UV-B radiation in such a way that scientists can use them to find answers to many ecological questions. According to the paper published in Methods in Ecology and Evolution, an online journal of the British Ecological Society, this data set allows drawing new conclusions about the global distribution of animal and plant species.

Average intensity of global UV-B radiation – mean UV-B of highest month. (Quelle: Tomáš Václavík/UFZ)

Average intensity of global UV-B radiation – mean UV-B of highest month. (Tomáš Václavík/UFZ)

Zoom

Average intensity of global UV-B radiation – mean UV-B of lowest month. (Quelle: Tomáš Václavík/UFZ)

Average intensity of global UV-B radiation – mean UV-B of lowest month. (Tomáš Václavík/UFZ)

Zoom

Many research projects study the effects of temperature and precipitation on the global distribution of plant and animal species. However, an important component of climate research, the UV-B radiation, is often neglected. The landscape ecologists from UFZ in collaboration with their colleagues from the Universities in Olomouc (Czechia), Halle and Lüneburg have processed UV-B data from the U.S. NASA space agency in such a way that they can be used to study the influence of UV-B radiation on organisms.

The basic input data were provided by a NASA satellite that regularly, since 2004, orbits the Earth at an altitude of 705 kilometres and takes daily measurements of the UV-B radiation. “For us, however, not daily but the long-term radiation values are crucial, as these are relevant for organisms”, says the UFZ researcher Michael Beckmann, the lead author of the study. The researchers therefore derived six variables from the UV-B radiation data. These include annual average, seasonality, as well as months and quarters with the highest or lowest radiation intensity.

In order to process the enormous NASA data set, the UFZ researchers developed a computational algorithm, which not only removed missing or incorrect readings, but also summed up the daily measurements on a monthly basis and determined long-term averages. The processed data are currently available for the years 2004-2013 and will be updated annually.

With this data set, scientists can now perform macro-ecological analyses on the effects of UV-B radiation on the global distribution of animal and plant species. “While there are still many uncertainties”, says Michael Beckmann, “the UV radiation is another factor that may explain why species are present or absent at specific sites.” The data set can also help addressing other research questions. Material scientists can identify strategies to provide better protection to UV-sensitive materials, such as paints or plastics, in specific regions of the world. Human medicine could use the data set to better explain the regional prevalence of skin diseases. “There are no set limits as to how researchers can use these data”, says Beckmann.

The data are now freely available for download on the internet and visually presented in the form of maps. These maps show, for example, that in countries in the southern hemisphere, such as New Zealand, the UV-B radiation is up to 50 percent higher than in the countries in the northern hemisphere, such as Germany. In general, the UV irradiation in winter is lower than in summer due to a shorter daily sunshine duration.

Background: Unlike the rather harmless UV-A radiation, the high-energy UV-B radiation causes health problems to humans, animals and plants. Well known is the higher risk of skin cancer in the New Zealand and Australia population if unprotected and exposed to sun for an extended period of time. Skin damage was also documented in whales and amphibians. In amphibians, UV-B radiation may also reduce survival rates of tadpoles and spawn eggs. In plants, the radiation reduces performance of photosynthesis, a process of using solar energy to convert carbon dioxide and water into sugars and oxygen. This inhibits production of biomass and thus reduces e.g. yields of agricultural crops.

The paper: glUV: a global UV-B radiation data set for macroecological studies

Michael Beckmann et al

Macroecology has prospered in recent years due in part to the wide array of climatic data, such as those provided by the WorldClim and CliMond data sets, which has become available for research. However, important environmental variables have still been missing, including spatial data sets on UV-B radiation, an increasingly recognized driver of ecological processes.

We developed a set of global UV-B surfaces (glUV) suitable to match common spatial scales in macroecology. Our data set is based on remotely sensed records from NASA’s Ozone Monitoring Instrument (Aura-OMI). Following a similar approach as for the WorldClim and CliMond data sets, we processed daily UV-B measurements acquired over a period of eight years into monthly mean UV-B data and six ecologically meaningful UV-B variables with a 15-arc minute resolution. These bioclimatic variables represent Annual Mean UV-B, UV-B Seasonality, Mean UV-B of Highest Month, Mean UV-B of Lowest Month, Sum of Monthly Mean UV-B during Highest Quarter and Sum of Monthly Mean UV-B during Lowest Quarter. We correlated our data sets with selected variables of existing bioclimatic surfaces for land and with Terra–MODIS Sea Surface Temperature for ocean regions to test for relations to known gradients and patterns.

UV-B surfaces showed a distinct seasonal variance at a global scale, while the intensity of UV-B radiation decreased towards higher latitudes and was modified by topographic and climatic heterogeneity. UV-B surfaces were correlated with global mean temperature and annual mean radiation data, but exhibited variable spatial associations across the globe. UV-B surfaces were otherwise widely independent of existing bioclimatic surfaces.

Our data set provides new climatological information relevant for macroecological analyses. As UV-B is a known driver of numerous biological patterns and processes, our data set offers the potential to generate a better understanding of these dynamics in macroecology, biogeography, global change research and beyond.

The glUV data set containing monthly mean UV-B data and six derived UV-B surfaces is freely available for download at: http://www.ufz.de/gluv.

 
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milodonharlani

Marine phytoplankton also affect climate by producing cloud condensation nuclei.

Tim Walker

Very interesting study. Thank you.

Merovign

The “sun has nothing to do with it” moment was when media-mainstream climatology “jumped the shark” for a lot of observers.
It was on the level of “there ain’t no such animal,” as the apocryphal zoo visitor said of the giraffe.

‘ New paper finds solar UV-B output is correlated to global mean temperature’
What ever happened to the doubters saying.’that correlation does not mean causation’? When it’s applied to releasing co2 and increased temperatures? Surely some mistake here?

Pay walled of course.
I’m curious to know if they published a temperature reconstruction versus the instrumental record? I’m kinda waiting to see if Leif pokes giant holes in this or not. But if not, then the correlation ought to diverge starting about 1950 or so if sensitivity to CO2 is significant.

Henry Clark

“the tiny 0.1% variations in total solar irradiance [TSI] over solar cycles, ignoring the large variations in solar UV of up to 100% over solar cycles”
And around 15% minimum-to-peak variation in cosmic ray flux over an ordinary solar cycle, plus more over the “global warming” since the Little Ice Age when average absolute terrestrial temperatures in Kelvin rose by around 0.3% (as in my usual multitude of solar-climate correlation demonstrations in http://tinyurl.com/nbnh7hq ).
Anyway, I’ll have to look more at this to piece out what is causing what part, since high versus low solar activity times differ in more than UV though it is a factor.

Robertvd

http://www.aemet.es/es/eltiempo/observacion/radiacion/ultravioleta?l=barcelona&f=anual
http://www.aemet.es/es/eltiempo/observacion/radiacion/ultravioleta?datos=mapa
I noticed that my birds don’t want to be in the direct sun and when they are sunbathing they go to the part were they can sit behind glass.

JJ

Anthony,

In the supplemental information (SI) I found this correlation map, which was telling for me. Note the red of highest correlation – mostly in the tropics.

All of the colored areas denote high (i.e. statistically significant) correlation. Only the gray areas denote low (i.e. not statistically significant) correlation. There is no gradation of high to low correlation provided, apart from the single p value criterion.
The high-high … low-low categories provide the “flavor”, not the strength, of the correlation. The dark red and dark blue areas denote high positive correlation – high UV with high temp, low UV with low temp. The baby red and light blue areas denote high negative correlation – high UV with low temp, low UV with high temp.
The authors call out the existence of the uncorrelated and inverse correlated areas as the new information provided by their study. They assert that the positive correlation is already accounted for in existing climate variables.

Rob

David, (1.55)
Sadly the data is only from 2004 as it is extracted from a NASA satellite sent up to monitor ozone so there will be nothing to compare to historically. No proxies in the paper, just daily UVB data which has been aggregated to give monthly numbers. Any correlations to temperature will interesting, but unlikely to lead to anything concrete for at least two solar cycles unless some intermediate steps in a postulated pathway can be studied (as Jesper Kirby has done for the cosmic ray/cloud hypothesis). The suggestions above about phytoplankton would be interesting as there are some experimental studies that could be done to see if (i) phytoplankton density does change with UVB and (ii) phytoplankton have an effect on cloud seeding.
Still interesting though.

milodonharlani

Rob says:
April 22, 2014 at 2:10 pm
The mixed effects of UV (primarily A) on phytoplankton have been studied:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1913777/
Not just direct effects however must be considered, if, as seems at least possible, there is also an indirect effect on ocean temperature.

milodonharlani

A 2008 study attributed the failure of GCMs to model Cretaceous climate on their ignoring the effect of clouds, which could have been reduced then by the depressing effect of unusually hot oceans on phytoplankton:
http://news.nationalgeographic.com/news/2008/04/080410-ancient-warming.html

pochas

Suggests to me that the “loopy jet stream” (aka the dreaded polar vortex) we have come to know and love is associated with variation in solar UV. The UV generates ozone, the ozone absorbs incoming SW, the Brewer-Dobson circulation moves the whole heated mass to the poles where a temperature inversion forms which destabilizes the polar vortex so that cold arctic air masses can move southward. This affects northern continental landmasses which are nearer the poles and provide an avenue for the cold air moving south, but not the southern continents except for small areas nearest antarctica. This may not by itself cause global cooling, as the northern oceans seem to warm as the continents cool. We will have to wait to see the longer term effects of the quiescent solar cycles.

kenw

..the 4th:
correlation is NOT causation, certainly. But it provides clues as where to look.
And despite the rhetoric, anthropogenic CO2 and warming have precious little correlation.

Robertvd

If more UVB warms the oceans even more there should be more cloud formation that stops much of this radiation reaching the surface.
This morning we had rain in Barcelona .And the rest of the day had variable clouds.
http://www.aemet.es/es/eltiempo/observacion/radiacion/ultravioleta?l=barcelona

pochas

Had it backward. Strong UV creates the temperature inversion which stabilizes the polar vortex and the cold air stays put. Weak solar cycles remove the temperature inversion and destabilize the polar vortex so that cold air moves southward and northern oceans warm. Sorry!

cnxtim

By all means my jolly climate scientists, continue to examine and measure and when you feel quite confident predict the future weather, accurate forecasts are most useful.
But please give up this pursuit of the myth of CAGW and expecting taxpayers to fund your folly.
And also give up trying to blame “big oil” for everything that doesn’t happen to your liking in the world – the rest of us have REAL work to do that requires energy provided for the best all over ROI, .and that means exploiting our oil and gas reserves to depletion if there are no worthwhile alternatives beforehand.

thegriss

What they need to do is look at the changes in frequency of UV during solar maximums (there was a series of very strong solar maximums during the latter half of last century). There are significant changes in sea water penetration in the 300-350 nm range which would have a significant effect algal growth. as well as warming of the surface.
http://solarphysics.livingreviews.org/Articles/lrsp-2008-3/download/lrsp-2008-3Color.pdf

The plot here shows a spatial correlation of BIO1 with UVB. BIO1 is a mean (normal) annual temperature. It seems to be just an eco climate classification – not time-varying temperature data. It’s just saying that hot places get more UV-B. This may be important for ecologists to know, but it doesn’t tell anything about the Sun and climatic variations.
REPLY: Well if the actual paper wasn’t paywalled so that only high-preists of eco-sci can look at it, I’d have gladly provided such a plot if they had it. Rather than whine about it Nick why not use your status as an insider and get us a copy to look at? – Anthony

Henry Clark

Actually looking a bit more at this:
This, as in the quadmap, may be mainly merely a glorified version of such as finding that sunny near-equatorial lands tend to be hot (and have high UV-B too), far from the kind of correlation over time demonstration which is more relevant and which I prefer.
For example, the Sahara desert has high UV, high sunlight, and of course is hot. That’s not what is most interesting to see, rather that patterns in solar activity match patterns in temperature over the decades (my usual http://tinyurl.com/nbnh7hq ).

george e. smith

Well the first think I noticed about their four color map, is that the oceans are all white, so it would seem they aren’t talking about oceanic algae. And how could ocean algae affect albedo much.
If some critter or other doesn’t absorb sunlight /UV in the deep ocean, well it just keeps on going till something does. So UV absorption in the ocean, must be total. I suppose some algae types might reflect some other colors, but the UV is going to get absorbed by something; animal, vegetable or mineral.
But it sounds like an interesting paper to get out from under the bushel.

Henry Clark

Nick Stokes preempted my post by 1 minute it looks like, though I was writing it since several minutes ago, but that is the idea.

TimB

More likely that it’s affecting atmospheric chemistry of ozone at TOA. Ozone is a greenhouse gas which IPCC regards as about 25% effective as CO2. UV-B also interacts with aerosols which also interacts with ozone. If this is done by satellite, it’s not clear how much would be reaching the surface. The answer lies in between stratosphere and troposhere.

son of mulder

” blackadderthe4th says:
April 22, 2014 at 1:49 pm
What ever happened to the doubters saying.’that correlation does not mean causation’? When it’s applied to releasing co2 and increased temperatures?”
But CO2 has been rising for the past 17 years and temperature hasn’t so what are you talking about?

Rhoda R

The interesting thing about this and some other recent studies is that the publishing portion of the science world is beginning to acknowledge that something other than CO2 may be driving climate.

[SNIP Mosh, stop leaving cryptic half-comments, please. If you have something to say, say it. Don’t make people try to reverse engineer what you are snarking on about – Anthony]

Steve from Rockwood

Satellites are great.

Duster

blackadderthe4th says:
April 22, 2014 at 1:49 pm
‘ New paper finds solar UV-B output is correlated to global mean temperature’
What ever happened to the doubters saying.’that correlation does not mean causation’? When it’s applied to releasing co2 and increased temperatures? Surely some mistake here?

Correlation does not mean causation, but the “not the sun” crowd have been arguing that the sun is NOT correlated. Thus an assertion has been falsified, which in science means progress has occurred.

Blackadderthe4th sys:
“What ever happened to the doubters saying.’that correlation does not mean causation’? When it’s applied to releasing co2 and increased temperatures? Surely some mistake here?”
We use common sense here. In the case of warming/CO2, we all know increased levels of CO2 causes warming and also that warming causes CO2 levels to increase. We also know an increase in Earth warming cannot affect solar UV-B output. Obviously the Earth is warm because of solar radiation, so it’s hardly a giant leap to assume, should someone wish to, that large variations in an important type of solar radiation will lead to some variation in Earth temperatures, in one fashion or another, yet to be spelled out in a definitive manner. As for your claim that doubters deny
correlation of CO2 / global temps (which is a falsehood and a straw man, elementary school logic), it would be more difficult for you to show that a strong correlation exists, given the rapid and gigantic increase in CO during the past two decades, accompanied by zero global warming. Correlations are a huge problem for the hysterical alarmist crowd, not for the realists.

DesertYote

These data seem more relevant to ecology then to climatology, which is fine by me. I am much more interested in ecology anyways. I grew up were most of the plants have evolved mechanisms that shield them from the impact of UVB. The same mechanisms can be found in the plants of the Andes. BTW, when you climb Everest, be sure to bring your sun block.
Using my aging Eyeball v 1.0, it seems that the distribution is a function of latitude, elevation, and humidity.
Like has been noted, it is going to take a lot more data to prove any connection between the spectral distribution of the suns output and climate, not that I am discounting the possibility.

milodonharlani

TimB says:
April 22, 2014 at 2:48 pm
Ozone is unusual if not unique among GHGs in being a monatomic molecule.

“Whatever happened to the doubters saying.’that correlation does not mean causation’? When it’s applied to releasing co2 and increased temperatures? Surely some mistake here?”
Yes, the mistake is that CO2 does not correlate with temperature, increased or decreased! Temperatures have not risen for 17 years, while CO2 levels have.
This study shows something interesting instead.‘ New paper finds solar UV-B output is correlated to global mean temperature’

Mike Maguire

“Although the total (and visible) irradiance has only increased by roughly 0.3% since the Maunder minimum the enhancement of UV and NUV radiation during the last 3
centuries is ten and four times larger, respectively.”
Conclusions:
“The ozone abundance in the Earth’s atmosphere is influenced strongly by the level of solar UV radiation (e.g., Haigh 1994). Knowledge of the evolution of the solar spectral irradiance is therefore important for obtaining an idea of long-term changes in stratospheric chemistry and possible associated climate changes”
http://www.landscheidt.info/images/UV_solanki.pdf
I am also interested in vukcevic’s take and graphs related to this.

Rob says:
April 22, 2014 at 2:10 pm
David, (1.55)
Sadly the data is only from 2004
>>>>>>>>>>>>>>
Thanks Rob. I agree the study is interesting, but from the perspective of climate…pffft, not nearly enough data.

milodonharlani

ntesdorf says:
April 22, 2014 at 3:08 pm
Given enough time, movements in CO2 concentration do correlate with temperature, because a colder ocean will hold more gas & a warmer one give up more to the air. But that’s the reverse of the cause-effect relationship falsely posited for CACA.
During the Precambrian earth’s atmosphere was largely the product of outgassing from the mantle. More than four billion years ago, CO2 concentration was on the order of one atmosphere of pressure, gradually decreasing to ~1/100 atm (~10,000 ppm) by one billion years ago. Precambrian atmosphere aggressively weathered Fe, Ca & Mg-rich minerals. Present atmospheric CO2 (~400 ppm) level results from gradual reaction of the gas with these minerals & from metabolic activity of life. Natural CO2 sequestration (for example by cyanobacterial carbonate precipitation) started in the Archean, later to involve eukaryotic life.
In the late Precambrian, ie c. 1,100,000 years ago, the sun would have been about 10% less powerful than now, but with 10,000 or more ppm CO2 (some say a lot more), why was that time a super Icehouse World? Even in the Cambrian & Ordovician, Icehouse conditions were common, with CO2 levels around 7000 ppm & the sun just four to five percent less potent. Moving on to the late Carboniferous & early Permian Periods, there was however an Icehouse World with CO2 levels similar to now & the sun less than three percent weaker. Even so, clearly other factors are more important in the onset of cold climatic conditions than CO2 concentration.

milodonharlani

Sorry. Meant 1,100,000,000 years, ie 1.1 billion.

Ulric Lyons

Given that the UVB is higher at high altitudes and lower in the tropical forest regions:
http://www.ufz.de/export/data/1/57980_UVB3_Highest-Month.jpg
I suspect that water vapour plays a large part:
http://onlinelibrary.wiley.com/doi/10.1002/grl.50935/abstract
And then there’s those pesky holes in the water vapour through the tropical regions:
http://www.fourmilab.ch/cgi-bin/Earth/action?opt=-p&img=vapour.bmp

clipe

blackadderthe4th says:
April 22, 2014 at 1:49 pm
‘ New paper finds solar UV-B output is correlated to global mean temperature’
What ever happened to the doubters saying.’that correlation does not mean causation’? When it’s applied to releasing co2 and increased temperatures? Surely some mistake here?

Jumping in with a knee-jerk comment before “the doubters” had a chance to read the paper makes you look stupid.

Jeff

This raised a red flag (for me at least, I’m not fond of massively-massaged data, Murphy’s Law, I guess):
“In order to process the enormous NASA data set, the UFZ researchers developed a computational algorithm, which not only removed missing or incorrect readings, but also summed up the daily measurements on a monthly basis and determined long-term averages.”
With what (if anything) did they replace the missing readings?
How did they determine readings were incorrect? Threshhold values?
“The processed data are currently available for the years 2004-2013 and will be updated annually.”
Good.
“The data are now freely available for download on the internet and visually presented in the form of maps.”
Better…now about that paywall…..
“…New Zealand, the UV-B radiation is up to 50 percent higher than in the countries in the northern hemisphere, such as Germany…”
Except if you add back in all the radiation from the tanning parlors… 🙂 Actually they also talk about radiation effects/health…there were some specialists on another thread discussing a similar issue, would be interesting to get their views….
This sounds promising, would be nice to see the whole study (at least the data is supposed to be available, but the methods should be there too for validation/invalidation/what-have-you…
Waiting for a response from the halls of Svaalgard….

Konrad

As George E. Smith has noted the plot does not cover the oceans. In considering solar influence on climate, the oceans are important. This study looks at higher energy UV-B, but even UV-A still has the power of 10 w/m2 at 50m depth in the oceans. It is the UV frequencies that vary most between solar cycles.
Most of the solar radiation reaching the oceans is UV, SW and SWIR. As can be seen from the diurnal overturning above the themocline it is UV and SW rather than SWIR (shallow penetration) that have the most influence on ocean temperatures*.
When the oceans are considered a near blackbody, the cumulative effects of UV variation are ignored.
*If DWLWIR and solar SWIR were having a huge effect on ocean temps, how much diurnal overturning would there be? 😉
REPLY: Air temperature over nearby land is highly dependent on the oceans, and that was my point – Anthony

Robertvd

“In plants, the radiation reduces performance of photosynthesis, a process of using solar energy to convert carbon dioxide and water into sugars and OXYGEN.”
How fast could O2 levels drop ?

” I’d have gladly provided such a plot if they had it. Rather than whine about it Nick why not use your status as an insider and get us a copy to look at? – Anthony”
I have read the paper. It refers just to temperature data in the Bioclim dataset (as in the SI), and to Terra-Modis annual mean SST. These are spatial distributions of long term means. Unfortunately, the paper’s pdf does not allow me to copy the text.
The words you have highlighted from the abstract (in your title),
“UV-B surfaces were correlated with global mean temperature and annual mean radiation data”
have two possible meanings. We’re used to thinking of time correlation of spatial means. But it can equally mean spatial correlation of time means. Since they have cited a dataset of spatially distributed time mean temperatures, and used LISA to get the spatial correlations, it’s clear that they are using the second interpretation. Which doesn’t tell us anything about climate changing over time.

Konrad

“Air temperature over nearby land is highly dependent on the oceans, and that was my point – Anthony”
————————————–
Yes, you did point that out, and I jumped straight to the SI and missed it 🙁
Another older paper that deals with UV into the oceans –
http://www.biblioteca.uma.es/bbldoc/tesisuma/1663844x.pdf
This also a biology paper. Figure 3.(d) has a good plot of some frequencies vs. w/m2 at depth.

@BA4 – Correlation does not mean causation. But it is worth looking into. Given CO2 has no correlation, why are people wasting their time with it?

KevinK

Ah, yes, some folks may have finally realized that calculating absolute radiometric values (i.e. the alleged radiative imbalance) actually requires accurate data across the entire spectrum of light (cosmic rays, X-rays, UV-B, UV-A, visible, NIR, MWIR, LWIR, etc.). Sure, the visible light may be quite stable, but the other components (where few folks have bothered to look) may vary widely.
Once it’s absorbed and becomes heat the spectrum of the incoming light matters little.
And a simplistic “theoretical black body” spectrum used in models is very naive. Every real observed source of light from incandescence like candle flames and halogen lamps (not coherent sources like lasers) has a spectrum that “approximates” a theoretical black body. The key word is “approximates”. If you measure the real absolute radiometric values (i.e. how much energy is actually emitted by that source) with a spectroradiometer you find that a real light bulb radiating at an approximate 3100K may differ in absolute radiometric energy by 5-10% from the theoretical black body. These differences alone are enough to “wash away” the alleged “radiative imbalance”.
I might be mistaken, but I think I remember questioning the paucity of absolute data regarding UV light levels reaching the Earth’s surface. But then again I question lots of things.
Nice new insight for the climate science community. Yes, it only shows a correlation (temperature and UV-B) so far, but that is more than the “CO2 commands Temperature” believers have demonstrated.
Cheers, Kevin.

Janice Moore

From my annotated summary of:
Gray et al. 2010 — {http://pubs.giss.nasa.gov/docs/2010/2010_Gray_etal_1.pdf}
Abstract (in part):
“Understanding the influence of solar variability on the Earth’s climate requires knowledge of
1) solar variability,
2) solar-terrestrial interactions and the
3) mechanisms determining the response of the Earth’s climate system.
We provide a summary of our current understanding in each of these three areas.”
Gray, L.J., J. Beer, M. Geller, J.D. Haigh, M. Lockwood, K. Matthes, U. Cubasch, D. Fleitmann, G. Harrison, L. Hood, J. Luterbacher, G.A. Meehl, D. Shindell, B. van Geel, and W. White, 2010: Solar influence on climate. Rev. Geophys., 48, RG4001, doi:10.1029/2009RG000282.
Re: UV and Climate
1. Solar Variability Generally
“… we acknowledge the possibility that short‐term processes which occur repeatedly may lead to an integrated longer‐term effect.” [Gray, et. al. at 6]
Comment: Is there any evidence of such long-term effects?
2. UV Measurement
“Improvements made to date suggest that UV irradiance during the Maunder Minimum was lower by as much as a factor of 2 … . However, this work is still in its infancy. The model estimates match observed spectra between 400 and 1300 nm very well but begin to fail below 220 nm… .” [Id. at 9]
3. Ozone — Stratospheric
“Ozone is the main gas involved in radiative heating of the stratosphere. Solar‐induced
variations in ozone can therefore directly affect the radiative balance of the stratosphere with indirect effects on circulation. Solar‐induced ozone variations are possible through[:]
(1) … UV spectral solar irradiance, … modifies the ozone [Id. at 12] production rate through photolysis of molecular oxygen, primarily in the middle to upper stratosphere at low latitudes [Haigh, 1994][;]
(2) changes in the precipitation rate of energetic charged particles,… primarily at polar latitudes [e.g., Randall et al., 2007][; and
3)]… transport‐induced changes in ozone … [from] indirect effects on circulation caused by the above two processes. … On the 11 year time scale, the mean irradiance near 200 nm has varied by ∼6%, over the past two solar cycles … [Id. at 13]
In the upper stratosphere where solar UV variations directly affect ozone production rates, a statistically significant response of 2% – 4% is evident. … The density‐weighted height integral of ozone at each latitude gives the “total column” ozone, and a clear decadal oscillation in phase with the 11 year solar cycle is evident in both satellite data … The ozone response
in the lower stratosphere is believed to be the main cause of the total column ozone signal because of the high number densities at those levels.” [Id.]
Comment: So far, only lower stratosphere shows evidence of a significant ozone signal. What evidence is there that this is ultimately propagated to Earth’s climate?
4. Models and UV – Ozone Mechanism
” Atmospheric models that include a good representation of the stratosphere, including interactive ozone chemistry, are available, but they do not generally include a fully coupled ocean at present. The prime solar mechanism for influence in these models is therefore the change in stratospheric temperatures and winds due to changes in UV irradiance and ozone production, and the influence on the underlying troposphere and surface climate involves stratosphere‐ troposphere coupling processes. This mechanism is often referred to as the top‐down mechanism … .” [Id. at 24-25 — emphasis mine]
” … latent heat flux anomaly across the air‐sea interface of ∼0.5 W m−2, which was larger than the direct solar radiative forcing by a factor of ∼3 and also explained the correct phase of the response. This therefore represents a different kind of amplification of the 11 year
solar cycle and is not associated with changes in trade wind strength or cloud cover since these did not have the correct magnitude or phase. This result implies a role for the top‐down influence of UV irradiance via the stratosphere. White et al. [2003] also noted that time sequences of tropical tropospheric temperatures lead those in the lower stratosphere, which appears to argue against the top‐down influence. They suggest, however, that this should not be interpreted as a tropospheric signal forcing a stratospheric response because the stratospheric temperature response appears to be in radiative balance and hence is in phase with the 11 year
solar cycle, while the troposphere responds to anomalous heating and advection which peaks during the period leading up to solar maximum and not at the maximum itself. This is a good example of the difficulties and dangers of interpreting observed signals from different parts of the atmosphere and especially in using their time response to try to infer cause and effect.” [Id. at 26 — emphasis mine]
“More recent improved models … simulat[e] an improved vertical structure of the annual mean ozone signal in the tropics, … However, it is still not clear to which factor (SSTs, time‐varying solar cycle, or inclusion of a QBO) the improvements can be ascribed. … despite these general improvements, there are many details that are not reproduced by models. Further studies, including fully coupled ocean‐troposphere‐stratosphere models with interactive chemistry, will be required to improve the simulated ozone signal and distinguish between the various influences.” [Id. at 27-28 — emphasis mine]
5. Stratosphere — Troposphere Coupling Mechanisms
” … at equatorial latitudes Salby and Callaghan [2005] identified an interaction between the stratospheric B‐D circulation and the tropospheric Hadley circulation … but again, this does not provide a chain of causality.” [Id. at 29 — emphasis mine]
There are many proposed mechanisms for a downward influence from the lower stratosphere into the troposphere … response in tropical vertical velocity was not uniformly distributed in longitude but was largest over the Indian and West Pacific oceans, … despite having imposed SSTs, suggesting that their tropospheric signal was a response to changes in the stratosphere and not to the bottom-up mechanism of TSI heating of the ocean surface … .
This would be consistent with the results of Salby and Callaghan [2005] (see Figure 25), whose analysis suggested that the stratosphere and troposphere are linked by a large‐scale transfer of mass across the tropopause resulting in a coupling of the B‐D circulation in the stratosphere and the tropical Hadley circulation in the troposphere. However, as discussed in section 4.2.2, this does not preclude the possibility that there is an additional positive feedback from the oceans so that both top‐down and bottom‐up mechanisms are acting in the real world.” [Id at 30 – emphasis mine]
Much work is still required to fully characterize the nature of these complicated
interactions and hence to verify these mechanisms
. … Although details of the mechanisms involved are still not fully established, it is becoming increasingly clear that the top‐down mechanism whereby UV heating of the stratosphere indirectly influences the troposphere through dynamical coupling is viable and may help to explain observed regional signals in the troposphere.” [Id. at 32 — emphasis mine]
6. UV –Ozone Mechanism v. ENSO (El Niño Southern Oscillation)
“… UV‐ozone feedback mechanism appears to cause enough heating near the tropical tropopause to significantly affect the tropical hydrologic cycle, with regional impacts on
precipitation that are also broadly similar to those related to ENSO changes… .” [Id. at 33]
Comment: It may be entirely ENSO which is the controlling forcing. Is the relative strength of ENSO v. UV-solar precipitation forcing known?
7. Re: Attributing Causation of Climate
” … correlation coefficients, which suggest a link but are not sufficient to indicate any causal mechanism. In addition, there is substantial internal variability in the climate
system,… . Since the climate system may react in a nonlinear way the response function can be quite different from the forcing function… .” [Id. at 24 – emphasis mine]
(from: Summary of Gray, et. al. by Janice Moore)

Louis

“…in countries in the southern hemisphere, such as New Zealand, the UV-B radiation is up to 50 percent higher than in the countries in the northern hemisphere, such as Germany.”

Does anyone know why that is the case? They’re not comparing New Zealand in the summer to Germany in the winter, are they? The Earth is closer to the sun during the southern hemisphere summer. Would that make that much difference in UV-B radiation?

milodonharlani

Louis says:
April 22, 2014 at 6:39 pm
It’s because of stratospheric ozone differences, not incoming UVB variance:
http://www.researchgate.net/publication/232784832_Increased_ultraviolet_radiation_in_New_Zealand_%2845deg_S%29_relative_to_Germany_%2848deg_N%29

Louis

blackadderthe4th says:
‘ New paper finds solar UV-B output is correlated to global mean temperature’
What ever happened to the doubters saying.’that correlation does not mean causation’?

Where did you see the term “causation”? Perhaps by “correlated” they didn’t mean causation, they meant correlated. Isn’t it a bit ironic for someone to see the word “correlated” in a sentence, assume it means “causation,” and then complain about correlation not being the same thing as causation? The way that expression is thrown around, I would think that some people believe correlation disproves causation. If so, they’re probably also mystified by what causes pregnancy to occur. Often correlation does mean causation. It just doesn’t “prove” causation. But if you want to establish a linkage, correlation is usually the first place you start.

Anthony why would you snip a simple instruction for people to
LOOK AT THE DATA SOURCE.
It’s pretty simple. Many people yourself included spend a huge amount of time criticizing two sources of data for temperatures: CRU and GHCN. Of The two surface datasets they reference ( its unclear which they use for correlation ) one relies on CRU — actually the harry-read-me data, and the other (created by my friend) relies on GHCN adjusted and a variety of other stations.. interpolated using AUSPLINE down to 1 km. Neither are suited for climate studies and are targeted more at biology studies and species study.
REPLY: It wasn’t simple, it was cryptic, and with snark. If you have an issue, spell it out, because I’m done with your drive-by snark, all it does it confuse people and make you look like some of the snottier-than-thou people we deal with. Be the friend you claim you are, spell it out. – Anthony

Mike Maguire

“It’s because of stratospheric ozone differences, not incoming UVB variance”
Could changes in the structure and strength of earth’s magnetic field in those locations be having an impact(altering stratospheric ozone)