One of the big problems of climate science is uncertainty. Some things that always seem to be in flux are historical datasets, partly because, well, they have so much inherent uncertainty built in. Such is the case of the Historical TSI plot presented on the University of Colorado SORCE web page. All of the sudden, with little fanfare, it changed, and not just a little. What is interesting are the drops during the Maunder Minimum as well as our current Solar Cycle 24
Readers may know that a controversy persists as to the actual TSI behavior in the late 80s/early 90s. The so called “ACRIM gap” was created when the Challenger shuttle was destroyed in a famous accident due to mismanagement combined with launch pressure. It caused by the delay of the shuttle-launched ACRIM2, a satellite that was to maintain continuity of TSI measurements. The debate over how to bridge the gap is relevant to the explanation of the warming that persisted into the 90s. The debate has been quite heated, with those invested in the IPCC forcing story claiming that the TSI decreased in the 90s and those (Willson and Scafetta) who argued that the TSI continued to increase in the 90s.
Some previous TSI reconstructions:
Now there’s even more tinkering from SORCE:
http://lasp.colorado.edu/home/sorce/data/tsi-data/#plots
The SORCE TSI reconstruction looked like this a month ago (word BEFORE added):
Here is what it looks like as of today (word AFTER added):
They say this about it today:
This historical reconstruction of TSI is based on that used in the IPCC AR5 Working Group’s Assessment Report and based on TSI reconstructions by Krivova et al. (JGR 2010) and Ball et al. (A&A, 2012). The values from their SATIRE model have been offset -0.30 W/m2 to match the SORCE/TIM measurements during years of overlap and then extended using SORCE/TIM annual averages from 2003 onward. The historical reconstruction provided here was computed by G. Kopp using TIM V.15 data in February 2014, and is updated annually as new TIM data are available.
Download the ASCII data file
Explore the data interactively with LISIRD
Since the previous dataset wasn’t available to me to plot to show differences and comparisons, here is an overlay of the 2013 and 2014 image versions of the plot, scaled to fit properly since the Y axis changed in 2014 to accommodate the greater range:
They have changed the last three solar maxima and now show a clear roll-off since about 1975. Those are enormous changes since last year’s dataset.
Of note is the drop of about 0.3 w/sqm during the last minimum. You’d think they have a measurement handle on that with our current satellite platform, so you have to wonder why that would need adjustment.
Also of note is a drop of about 0.2w/sqm during the Maunder Minimum.
Not only is global temperature adjusted and is a constantly moving target, now so it is with solar irradiance. With so much input data in flux, the “uncertainty monster” of climate modeling output keeps growing.
h/t to Gordon Fulks and Aaron Smith
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The model used [SATIRE – not a pun] is based on the Group Sunspot Number which we now know is about 50% too low before the 1880s. The arguments for this can be found here: http://www.leif.org/research/CEAB-Cliver-et-al-2013.pdf and in more detail here http://www.leif.org/research/Reconciling-Group-and-Wolf-Sunspot-Numbers.pdf and here http://www.leif.org/research/Solar-Petaluma–How%20Well%20Do%20We%20Know%20the%20SSN.pdf
so no wonder there is a problem. On the other had, it is also true that we do not KNOW for sure if there is an ever-rising ‘background’, see here: http://www.leif.org/research/Long-term-Variation-Solar-Activity.pdf
My own assessment is that there [is] no evidence for a secular upward trending background.
These are indeed large changes. I note that the lower end of the range is now about 1360.0 rising to about 1360.7, whereas Leif’s goes from around 1365.6 to 1365.7. Even Judith Lean’s is consistently higher than the new measure. Are these really attempted measures of the same thing?
Interesting. Thanks for noticing and posting this here.
Layman here; could it be being adjusted as the recently found the large change in UV over the solar cycle?
Mike Jonas says:
February 10, 2014 at 7:04 pm
These are indeed large changes. I note that the lower end of the range is now about 1360.0 rising to about 1360.7, whereas Leif’s goes from around 1365.6 to 1365.7.
That difference of about 5 W/m2 is artificial in the sense that pre-SORCE data had a systematic error [due to scattered and diffracted light]. Correcting for that systematic error brings the two scales into agreement for the satellite era since 1978.
More on tinkering with the TSI data in the past, including a letter from astrophysicist Richard C. Willson (head of the ACRIM satellites) stating “Fröhlich [and co-author Judith Lean] made unauthorized and incorrect adjustments… He did it without any detailed knowledge of the ACRIM1 instrument or on-orbit performance…The only obvious purpose was to devise a TSI composite, that agreed with the predictions of Lean’s TSI proxy model.”
http://hockeyschtick.blogspot.com/2010/06/judithgate-update.html
Alec aka Daffy Duck says:
February 10, 2014 at 7:07 pm
Layman here; could it be being adjusted as the recently found the large change in UV over the solar cycle?
No, because those changes are too minute in energy terms [although large in percentages]
Hockey Schtick says:
February 10, 2014 at 7:09 pm
Richard C. Willson (head of the ACRIM satellites) stating “Fröhlich [and co-author Judith Lean] made unauthorized and incorrect adjustments
One does [NOT] need to have authorization to correct what one finds to be wrong.
One does NOT need to have authorization to correct what one finds to be wrong.
No, Leif gave me 1361 as TSI year round average a few weeks ago.
But HIS source was all over the place over the years, each “official” reading lower than the previous “official” reading due to calibration issues. It’s validated based on a source I trust, so all can use below as they see fit.
When I calculate radiation at TOA for each day of the year, I assign a single yearly average as TSI to the spreadsheet as a variable ..
Then calculate each day-of-year TOA value from
TSI_DOY=TSI*(1+0.0342*(COS(2*3.141*((F1-3)/365))))
ANY daily radiation absorbed or reflected calculation uses the DAILY TSI value, never a yearly average or a wikipedia-approved “everybody-knows-it” value.
This assumes that maximum radiation = 1408 on 3 January.
Wow, I see why people get so sarcastic about NOAA and NASA and such on this site now. I have also thought, as have others, that whenever possible we should do reconstructions of all the many graphs/data sets, etc. that begin in 1979 to show what they would look like starting a few years or decades earlier. I think they are tinkering with Great Lake ice coverage this year as well. But in this case we have a unique opportunity. At or near peak ice coverage, if someone will fly over Lake Michigan especially, but also hopefully Lake Superior and Ontario … on a clear day and take video … we could see if they have been tampering and how much.
RACookPE1978 says:
February 10, 2014 at 7:12 pm
But HIS source was all over the place over the years, each “official” reading lower than the previous “official” reading due to calibration issues.
I long ago pointed out that they had degradation problems, see e.g. here http://www.leif.org/research/PMOD%20TSI-SOHO%20keyhole%20effect-degradation%20over%20time.pdf
They have now acknowledged the problem [but still not corrected their dataset].
lsvalgaard says:
February 10, 2014 at 6:57 pm
This is the kind of article where I really appreciate having you around.
OK, but that now brings up a “calibration” problem of my own you may be able to help with:
When I digitize the daily (hourly) radiation charts (usually direct, indirect, and total are plotted for each 15 minutes) for a given year, then try to check the “requied” attenuation percent for that latitude and that day-of-year for that paper, do i need to “change” the yearly_average_TSI at the TOA for the YEAR when the measurement was made?
Clearly, if today’s TSI = 1361 was not 1361 in 2001 or 2008, or 1992 but some other value, then the plotted total radiation on ANY date that year will also have changed. If I assume a constant yearly_average_TSI and only correct for the day-of-year cycle, then my attenuation figures will be wrong, right? 8<)
On the other hand, the actual measured global or direct or diffuse radiation by some instrument doesn't care what happened on the sun's face, it is measured at what it is measured, right?
Bart says:
February 10, 2014 at 7:30 pm
This is the kind of article where I really appreciate having you around.
Yes, it is important that we get a dataset giving the correct energy input to the climate system.
RACookPE1978 says:
February 10, 2014 at 7:32 pm
If I assume a constant yearly_average_TSI and only correct for the day-of-year cycle, then my attenuation figures will be wrong, right? 8<)
Yes, there is a [real, true] solar cycle variation of 1 to 2 W/m2 [depending on the cycle], with maximum near sunspot cycle maximum. You can get the daily values since 2003 here: http://lasp.colorado.edu/data/sorce/tsi_data/daily/sorce_tsi_L3_c24h_latest.txt
RACookPE1978 says:
February 10, 2014 at 7:32 pm
On the other hand, the actual measured global or direct or diffuse radiation by some instrument doesn’t care what happened on the sun’s face, it is measured at what it is measured, right?
To evaluate the impact on the Earth, one should use the value reduced to the varying distance between the Sun and the Earth, which as you point out produces an annual variation some 70 times larger than the puny solar cycle variation everyone is so worked up about.
The motivation behind this looks clear! It explains the warming period out of the maunder min and the early 1900 warming until 1950. Then it show’s a clear discrepancy with temperatures from 1950 onwards, giving the impression that there must be another reason behind the continued warming. I expect to see papers citing this very information to show that ‘the sun did not cause the warming from the 50’s but could explain the current pause’ out very soon.
Tim says:
February 10, 2014 at 7:45 pm
The motivation behind this looks clear! It explains the warming period out of the maunder min and the early 1900 warming until 1950. Then it show’s a clear discrepancy with temperatures from 1950 onwards, giving the impression that there must be another reason behind the continued warming.
I think you are correct about the motivation. It is also good for funding.
I thought SORCE Tim had failed.
But 7 days of data shows up at Christmas which is right around the previous numbers. Still 0.4 W/m2 or so lower than expected at the top of the solar cycle but that is really nothing when divided by 4 and multiplied by 70% for Albedo.
0.07 W/m2 lower than expected, so what. It is still higher than normal given we are the top of the solar cycle so it is not contributing to the cooling, it is just contributing less warming than it should have.
——————-
And I don’t see how the historical TSI numbers can just be adjusted over and over and over again. We have absolutely no idea what the data should be now.
I think we have to back-up and just assume that it was much lower in the Maunder Minimum etc. because all these adjustments have just forced one to use reality and the cold temperatures of the late 1600s to say, yes, it was 4.0 W/m2 lower then. It just had to be.
And, therefore, the Sun is not the very stable Star we thought it was.
Well, Polaris’ intensity is varying much more these years than what it “should” …
the end times, they are nearer than they ever have been before.
(Which is a true statement every time it is uttered.)
The change of the SORCE TSI reconstruction is curious. In the 2013 TSI version the SORCE reconstruction was nothing but an extension of Lean TSI model.
In our recent paper, published a few weeks ago,
Scafetta, N., and R. C. Willson, 2014. ACRIM total solar irradiance satellite composite validation versus TSI proxy models. Astrophysics and Space Science (in press).
http://dx.doi.org/10.1007/s10509-013-1775-9
we demonstrate (figure 14), among many other things, that that SORCE TSI reconstruction based on Lean model failed to reproduce the TSI reduction from the TSI minima in 1996 to 2008-2009 as demonstrated by both the ACRIM and PMOD TSI composite.
It appears to me that now SORCE has tried to cover up the problem by reproducing a new TSI record made of an extension of Lean TSI model merged to the TSI PMOD composite since 1980. The PMOD is however shifted down to the ACRIM3 and TIM scale.
This is however a dangerous trick because as explained in our paper PMOD composite was originally based on altered TSI satellite measurements. The alterations were originally deduced from Lean TSI proxy model.
Thus, as explained in our new paper the fact that Lean’s proxy model failed to reproduce the TSI reduction from 1996 to 2008-2009 demonstrates also that PMOD composite is likely baseless.
In our figure 15 we show how TSI appears without the PMOD modification during the ACRIM gap with a possible forecast to 2020.
The paper can be download on my web-site.
In addition, in
Scafetta, N., and R. C. Willson, 2014. ACRIM total solar irradiance satellite composite validation versus TSI proxy models. Astrophysics and Space Science (in press).
http://people.duke.edu/~ns2002/pdf/10.1007s10509-013-1775-9.pdf
we demonstrates that Lean and Solanki TSI model have serious troubles.
The SORCE TSI seems now based on Solanki model which is carefully calibrated to reproduce the minima of the PMOD composite. However it fails to reproduce the maximum in 2002 which is too low and has other problems discussed in our paper.
Climate science, ever continuing to disappoint.
Small wonder Jones and co had so little regard for the original data.
Astrology is looking more credible every time the data gets “corrected”.
Given the variation in “measuring methods” is this reconstruction of any value?
Or do we just accept we have no useful data prior to the latest spaceborne instrumentation?
Bill Illis says:
February 10, 2014 at 7:52 pm
I thought SORCE Tim had failed.
It had, but there is still battery power enough to make a few measurements now and then, until the next satellite is launched.
We have absolutely no idea what the data should be now.
On the contrary, we know what the data should be now, it is the past [before 2003] that is murky.
I think we have to back-up and just assume that it was much lower in the Maunder Minimum …It just had to be.
I hope you realize that this is a circular argument.