From the American Geophysical Union:
Ultraviolet solar irradiance was low during recent solar minimum
Solar irradiance, which varies with the 11-year solar cycle and on longer time scales, can affect temperature and winds in the atmosphere, influencing Earth’s climate. As the Sun currently wakes up from a period of low sunspot activity, researchers want to know how irradiance during the recent solar minimum compares to historical levels. In addition to understanding the total received power, it is important to know how various spectral bands behave, in particular the ultraviolet, which causes heating and winds in the stratosphere.
Lockwood analyzes solar ultraviolet spectral irradiance data from May 2003 to August 2005 from both the Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) instrument on board the Upper Atmosphere Research Satellite (UARS) and the Solar Stellar Irradiance Comparison Experiment (SOLSTICE) instrument on the Solar Radiation and Climate Experiment (SORCE) satellite. Using several different methods to intercalibrate the data, he develops a data composite that can be used to determine differences between the recent solar minimum and previous minima. He finds that solar irradiance during the recent sunspot minimum has been especially low.
Source: Journal of Geophysical Research-Atmospheres, doi:10.1029/2010JD014746, 2011 http://dx.doi.org/10.1029/2010JD014746
Title: Was UV spectral solar irradiance lower during the recent low sunspot minimum?
Authors: Mike Lockwood: Space Environment Physics Group, Department of Meteorology, University of Reading, Reading, Berkshire, UK; and Space Science and Technology Department, Rutherford Appleton Laboratory, Didcot, Oxfordshire, UK.
Abstract:
A detailed analysis is presented of solar UV spectral irradiance for the period between May 2003 and August 2005, when data are available from both the Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) instrument (on board the Upper Atmosphere Research Satellite (UARS) spacecraft) and the Solar Stellar Irradiance Comparison Experiment (SOLSTICE) instrument (on board the Solar Radiation and Climate Experiment (SORCE) satellite). The ultimate aim is to develop a data composite that can be used to accurately determine any differences between the “exceptional” solar minimum at the end of solar cycle 23 and the previous minimum at the end of solar cycle 22 without having to rely on proxy data to set the long-term change. SUSIM data are studied because they are the only data available in the “SOLSTICE gap” between the end of available UARS SOLSTICE data and the start of the SORCE data. At any one wavelength the two data sets are considered too dissimilar to be combined into a meaningful composite if any one of three correlations does not exceed a threshold of 0.8. This criterion removes all wavelengths except those in a small range between 156 nm and 208 nm, the longer wavelengths of which influence ozone production and heating in the lower stratosphere. Eight different methods are employed to intercalibrate the two data sequences. All methods give smaller changes between the minima than are seen when the data are not adjusted; however, correcting the SUSIM data to allow for an exponentially decaying offset drift gives a composite that is largely consistent with the unadjusted data from the SOLSTICE instruments on both UARS and SORCE and in which the recent minimum is consistently lower in the wave band studied.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
UV, which is properly identified as a source of heat, can vary by as much as 6%. That’s huge compared to the variation in visible irradiance observed over the (typical) 11-year solar cycle.
This mere data can’t be right, cuz we all ‘know’ that CO2 is the sole driver of climate change, and the this and our other satanic gasses will doom us unless Govt takes over everybody’s lives.
Data, go away!
Looks like the full paper is behind a ‘pay wall”…$25. The 10 figures associated with the paper are accessible at the link provided above, however.
That Y axis, Watts per square meter, per nanometer (wavelength?)… It’s not not clear to me what those units actually tell us. Are they measuring the average drop in watts per nanometer of UV spectrum over a square meter?
> Title: Was UV spectral solar irradiance lower
> during the recent low sunspot minimum?
Lower than what? The previous minimum? If so, how much lower?
If you’re comparing to the previous maximum, then it should be no surprise that UV irradiance sinks proportionately lower during minima (more than TSI) because UV is associated with sunspot activity. (Look at the SDO EUV imagery. Guess what the bright spots are. EUV!). During minima there are fewer sunspots so UV goes down. Whereas TSI remains more ‘constant’ be cause the overall output doesn’t vary as much. No surprise there.
Also, look at the different offsets of the 4 instruments above. This has to be a calibration issue because they contradict each other at the overlaps. Greg Kopp indicates on his web page (http://spot.colorado.edu/~koppg/TSI/) that this long standing offset issue has been resolved, resulting in a lowering of the recalibrated TSI from 1366 to 1361 watts/m² normalized for 1AU at the top of the atmosphere:
http://europa.agu.org/?view=article&uri=/journals/gl/gl1101/2010GL045777/2010GL045777.xml&t=gl,2011,kopp
So I’m wondering if this ‘lower UV’ above isn’t somehow related to this recalibration, which means it really didn’t get lower but was readjusted for reality.
In the original claim that ozone decrease, especially over Antarctica, was due to CFCs they assumed the solar constant, including an unvarying UV portion of the spectrum. SInce UV creates ozone through the process of photodisassociation when it strikes oxygen in the atmosphere, the major mechanism that causes ozone variation was omitted. If you transfix the major cause of variation then an alternative explanation, usually a human one, is transcendent. The deception worked because few people are aware of the science. It is similarly true of climate science where the role of the Sun is effectively ignored.
How much did the ozone vary in this brief study, which tacitly acknowledges the error of the previous science?
SOLSTICE Gap, eh? Kinda like the ACRIM gap, then?
Tim Ball,
What, you mean all those expensive freon replacements, which obsoleted perfectly good and inexpensive hardware, and the requirements for evermore complex and fragile systems to handle
less efficient working fluids (some of which have working high head pressures nearing 500 psi)
have all been predicated on a scam ?..
DuPont probably makes a lot of campaign contributions
I’ve been seeing the data from the SORCE satellite for a while now.
Everyone had been saying the the TSI wasn’t changing, yet data shows that parts of the spectrum (including UV) varies wildly, even at minimum activity.
That’s why I’ve been trying to get input about a story I noticed LAST YEAR (12.17.10):
http://www.nasa.gov/topics/solarsystem/features/solarcycle-sorce.html
In which the statement was made:
“…Some of the variations that SIM [Solar Irradiance Monitor] has measured in the last few years do not mesh with what most scientists expected. Climatologists have generally thought that the various part of the spectrum would vary in lockstep with changes in total solar irradiance.
However, SIM suggests that ultraviolet irradiance fell far more than expected between 2004 and 2007 — by ten times as much as the total irradiance did — while irradiance in certain visible and infrared wavelengths surprisingly increased, even as solar activity wound down overall.
The steep decrease in the ultraviolet, coupled with the increase in the visible and infrared, does even out to about the same total irradiance change as measured by the TIM during that period, according to the SIM measurements…”
Notice it said that UV decreased, and IR increased.
Nice to see a peer reviewed paper finally picking up on it.
PS, for those that want to see the original data, it’s here:
http://lasp.colorado.edu/sorce/data/ssi_data.htm
Now waiting for Leif Svalgaard, Solar Astrophysicist Extraordinaire to swoop in, explain how this means virtually nothing important (per his own graphs), and all discussion will devolve to three or so regulars who will always argue with Leif, eventually about the same things as always, for the next three weeks at this same post as expected, even if another solar-related post pops up (they can all argue the same things on multiple posts at once).
Starting countdown: 4, 3, 2….
What was that quip from Einstein about the wavelenght of light and energy?
Since the energy increases as the wavelength shortens, in order to get a zero W/M^2, the Infrared would have to increase a lot more than the UV decreased. Right?
Thought this might come up, so here are some color composite SOHO images for each year on Nov 11/12 from 1996 to today( 09/19/11):
http://www.robertb.darkhorizons.org/EITNov1996_Nov2009.JPG
seeing that the AR’s on the EIT’s are a relevant subject matter.
Leif actually might agree on this, although he does correctly believe we have a real issue of instrument decay on these satellites (as noted in the paper) because GLORY should be measuring this by now and instead is sitting on the bottom of the ocean.
This is as big as clouds or anything else if the low UV heating continues if we enter a true solar minima.
There are actually 3 elements at play when the sun goes quiet.
1. The sun’s magnetic field weakens that allow greater penetration of high energy galactic cosmic ray into the inner solar system that results in greater cloud formation over the oceans.
2. The decrease in UV radiation emitted from the sun which slows down ozone production in the stratopause and upper stratosphere. (decrease of natural ozone)
3. The absence of major solar storms that destroy the ozone layer in the region above the stratopause. (increase of the recovery of natural ozone)
James-
Agree based on our current understanding, but our current understanding also still hinges on a rather invariate sun, which may be a very naive assumption
Free Freon.
========
The UV portion of incoming electromagnetic energy is minute compared to the IR portion of incoming.
Where UV interacts most with oxygen in the atmosphere, at the top of the tropopause, producing maximum ozone, (the ozone layer) there is no observable heating.
Yet incoming IR, 50% of solar radiation, is ignored. Except when the fact inadvertently slips out.
http://www.scientificamerican.com/article.cfm?id=huge-defunct-satellite
“NASA spokeswoman Beth Dickey confirmed with SPACE.com earlier today that the reason UARS is expected to fall early in its re-entry window is because of the sharp uptick in solar activity. Solar effects from the sun can create an extra drag on satellites in space because they can heat the Earth’s atmosphere, causing it to expand, agency officials have said.”
This explains the height rises over Greenland which caused the baltic UK winters..
“However, SIM suggests that ultraviolet irradiance fell far more than expected between 2004 and 2007”
and:
“The absence of major solar storms that destroy the ozone layer in the region above the stratopause. (increase of the recovery of natural ozone).”
Note that Joanna Haigh noted that from 2004 to 2007 ozone quantities rose in the region above 45km despite the quiet sun.
That would imply a natural warming above 45km when the sun is inactive and presumably a natural cooling above 45km when the sun is more active just as was observed in the late 20th century.
I see it as likely that the temperature of the stratosphere would follow the temperature of the mesosphere because the temperature of the mesosphere would affect the flow of energy from the stratosphere.
Thus the assumption that CO2 caused or contributed to the cooling stratosphere may well be false.
The temperature of the stratosphere affects the height of the tropopause which in turn affects the surface air pressure distribution and through that the speed of the water cycle and the speed of energy flow from surface to space.
More detail here:
http://climaterealists.com/index.php?id=6645
“How The Sun Could Control Earth’s Temperature”.
As far as I know all proposals other than mine involve a warmer stratosphere when the sun is active and a cooler stratosphere when it is inactive.
A couple of decades ago, we analytical chemists found many difficulties with accurate spectroscopy in the ultra violet in the controlled conditions of the laboratory, even when shining UV light through precise cells of known wall properties and dimensions. Shift the lab into the sky and insert a complex, time-variant atmosphere between source and detector and you have really tough problems. I’ve blogged before about dangers in assuming that satellite radiation measurements are not clipped or attenuated at the ends of their ranges; and how one cannot assume that UV is in lockstep with total radiation; and how UV reacts with earthly components like plants and oceans in ways quite different to IR. The science badly needs more spectroscopic resolution with satellite top-of-atmosphere devices. Guessing is so, so unreliable and unscientific.
However, I was comforted by the prescience of Al Gore, who wrote about the increase of solar UV hitting Patagonia, in his 1992 “Earth in the Balance” book. He documented that the UV light was causing blindness in rabbits and that fishermen were catching blind salmon (p. 85 in paperback). From these observations, ahead of their time, we can place a great deal of confidence on Al Gore’s other predictions, which are not only major, but so comprehensive that they can explain almost everything.
James Marusek mentioned:
“The decrease in UV radiation emitted from the sun which slows down ozone production in the stratopause and upper stratosphere. (decrease of natural ozone) and
The absence of major solar storms that destroy the ozone layer in the region above the stratopause. (increase of the recovery of natural ozone).”
On the basis of observations I think it will be found that the latter in affecting the mesosphere outweighs the former effect in the stratosphere so as to reverse the sign of the generally assumed solar effect on both stratosphere and mesosphere.
Thus both cool when the sun is active and warm when it is inactive.
If that proves to be so then not only is it relevant to climate changes but also it potentially invalidates the CFC proposition about human destruction of ozone.
henrythethird says:
September 20, 2011 at 6:35 pm
“I’ve been seeing the data from the SORCE satellite for a while now.
Notice it said that UV decreased, and IR increased”
That is something I would expect to see if the sign of the solar response in the stratosphere and mesosphere were to be reversed from that expected by standard climatology.
UV reduction might result in less ozone and so cooling of the stratosphere but could that be more than offset by more IR entering the stratosphere from the sun?
So we have two potential causes for a warming stratosphere when the sun is less active:
i) More solar IR affecting the stratosphere. This process is supported by the SORCE data, and/or
ii) Less ozone destruction and thus ozone recovery in the mesosphere with associated warming when the sun is less active. This is the option supported by Joanna Haigh’s ozone data.
The sun is nothing if not a variable star. Small variations but enough to affect climate.
This paper is focused on the UVc wavelengths which are largely absorbed by Ozone in the stratosphere. By inference the UVb wavelengths which cause the skin to go brown have also been at historic lows. This may be significant since these wavelengths are absorbed at depths of up to 100 metres in the oceans. This is important since red and infrared radiation from the sun and downward radiation from the atmosphere are absorbed within a few centimetres of the surface. This latter radiation forms the bulk of the energy absorbed by the oceans but because it is absorbed close to the surface it leads to evaporation or warming and re-radiation which quickly increases the energy loss until a balance is reached. So a change in the sun’s emissions at these wavelengths will lead to surface warming but little energy accumulation. Conversely the shorter wavelengths will be asborbed at depths that will lead to little or no change in the surface emissions and therefore energy accumulation will occur. Although it looks as though Svenmark’s cloud theory could well be true variation in solar UV may also contribute to long term warming and cooling of the deep oceans and then,through the natural cycles like ENSO, to subsequent release into the atmosphere to allow for eventual release to space.
From the abstract :
“All methods give smaller changes between the minima than are seen when the data are not adjusted; however, correcting the SUSIM data to allow for an exponentially decaying offset drift gives a composite that is largely consistent with the unadjusted data from the SOLSTICE instruments”
When was the last science experiment done where the data wasn’t adjusted? 1855?
kim says:
September 20, 2011 at 10:39 pm
Free Freon.
========
And give Halon back its Halo