Guest post by Guillermo Gonzalez
I recently happened upon the SORCE/TIM website and decided to look up the plot of the full total solar irradiance (TSI) dataset (http://lasp.colorado.edu/sorce/data/tsi_data.htm#plots)
The SORCE mission began collecting TSI data in February 2003.
I was curious to see if the variations in the TSI had begun to rise yet, perhaps indicating a start to cycle 24. Visual inspection of the SORCE TSI plot showed just the opposite – variations continue to decline in amplitude. If cycle 24 has started, there are no signs of it in these data.
We can be a bit more quantitative if we examine, instead, a plot of TSI variance with time. I produced such a plot using the daily average TSI data provided on the SORCE web site.
The red data are variance values calculated at two-week intervals. The blue curve is the smoothed data calculated in the same way as smoothed sunspot numbers (basically a 12-month running average). Note, the vertical axis is plotted on a logarithmic scale.
To compare the recent TSI variance trend with the previous sunspot minimum, I looked up the ACRIM2 daily average TSI data at: http://www.acrim.com/Data%20Products.htm
These data are plotted on the same scale as the SORCE data. The smoothed data show a minimum TSI variance near the beginning of 1996, some months before sunspot minimum (October 1996). Notice that the minimum value for the variance during the 1996 minimum was about an order of magnitude larger than the present TSI variance.
The SORCE web site quotes long-term 1-sigma precision (relative accuracy) of their TSI measurements to be 0.001%/yr. This corresponds to a variance of 2 ´ 10-4 W2 m-4. However, the precision should be considerably better than this on the 2-week timescale that I selected for calculating the variance. Unfortunately, I have not been able to locate a quote for the estimated precision of the ACRIM2 measurements. It would be worthwhile to know if the minimum TSI variance of the previous sunspot minimum measured by ACRIM2needs to be corrected for the instrumental precision.
Guillermo Gonzalez writes on his background:
I’m an astronomer, though my present title is associate professor of physics at Grove City College, PA. I wrote a paper (in Solar Physics) with Ken Schatten back in 1987 on predicting the next solar maximum with geomagnetic indices. That was my only contribution on anything having to do with the Sun-Earth connection, but I also got a letter published in Physics Today in 1997 wherein I urged readers to takethe Sun-Earth climate connection more seriously.
These days most of my research is on extrasolar planets.
UPDATE: I received a suggestion for an overlay via email from Terry Dunleavy and I’ve worked one up below. This was done graphically. I took great care to get the two lined up correctly. Note however that the datasets span different lengths of time, as you can note on the two timescales I’ve included on the combined graph. The vertical scale matches exactly between graphs though. – Anthony
UPDATE2: Here is another graphical comparison of the two TSI variance graphs, scaled to have a matching X-axis and appropriately aligned side by side. – Anthony
Robert Bateman (22:45:27) :
The actual behavior (as far as the current data shows) of Ice Ages is a rapid plunge to, and a very slow climb out of.
Other way around.
Paul Vaughan (00:53:45) :
the challenge, nor my immediate (right off the bat) suggestion that we leave the topic for another day to avoid going off-topic.
I think you have gone off-topic at length with personal attacks instead of answering my simple question as to where there tha challenge lies. My question still stands.
“WUWT is a great site and it would be an order of magnitude better if the moderators blocked the comments that get personal.”
Actually, I think the moderators here at WUWT are doing very well, excluding naked hostility but accommodating the reality that reason is the slave of volition and conviction.
Their discipline has, in fact, revealed to all that the myth of the well-mannered, ruthlessly logical, selfless ‘Scientist’ is a ludicrous characiture.
gary gulrud (06:50:08) :
the myth of the well-mannered, ruthlessly logical, selfless ‘Scientist’ is a ludicrous characiture.
Why are you so hard on poor Jim Hansen? Perhaps a bit of civility would be appropriate…
Dr. Svalgaard,
As we have recently considered (elsewhere) possible Jupiter’s thermal imbalance, is the science absolutely certain about the Earth’s thermal balance?
Since thermodynamics is one of the many of my weak points, I wander could you elaborate on the following:
1. An estimate of the average global temperatures (in relation to the current) if the Earth had a cold core (say 100K or less) with current TSI.
2. An estimate of the average global temperatures (in relation to the current) if the TSI was very low (say 5% or less of current) with the Earth’s core as present.
vukcevic (08:46:40) :
science absolutely certain
Science is never absolutely certain.
1.An estimate of the average global temperatures (in relation to the current) if the Earth had a cold core (say 100K or less) with current TSI.
Since the heat flow from the Earth is so minute, I don’t think we could measure any difference. But it is not reasonable in view of current knowledge to assume that the core of the Earth is at a low temperature of 100K [I assume that is -173C and not 100,000 degrees]. It is hot inside the Earth, for three reasons: 1) radioactive decay, 2) gravitational compression, 3) left over heat from formation.
2. An estimate of the average global temperatures (in relation to the current) if the TSI was very low (say 5% or less of current) with the Earth’s core as present.
Less than 58K. Something close to that of Pluto. But, your train of thought here escapes me. The questions do not seem to be [even remotely] connected to the actual situation.
My apologies not setting point one correctly. It should be:
1. An estimate of the average global temperatures (in relation to the current) if one was to assume that, in a hypothetical case the Earth had a cold core (say 100K or less in contrast whatever happen to be currently) with the current TSI.
Train of thought: An odd way of approaching problem: take two extreme cases by eliminating variables, and work towards point of balance.
Case 2. I was expecting much higher considering that T starts going up at depths of 30m or so (?).
I should have added in both cases: with the atmosphere and the rest (land / oceans ratio) as it is.
vukcevic (10:28:30) :
My apologies not setting point one correctly.
The heat flow [currently is of the order of 60 milliwatts or so, compared to TSI’s 340 W/m2, so about 5000 times smaller. The temperature effect of that is 4 times smaller, so 1/20,000 of 288K or 0.014 K. But I do not understand “say 100K or less in contrast whatever happen to be currently”. This could mean A: T < 100k, or B: T < 6000K – 100K = 5900K. Which is it?
Case 2. I was expecting much higher considering that T starts going up at depths of 30m or so (?).
T = (S/a)^(1/4), so for S= 0.06 W/m2 and a = 5.67E-8 [SI units], we get T = 32K if TSI falls to zero. If TSI is non-zero, the temperature is higher, 58K for your case of 5%.
Thanks for that.
In interim I was using oceans (75% of the surface), and 0.1W/m2, to calculate disappointingly miserable 42K which tallies with your result.
I suggested level of 100K to make contribution to the surface negligible (did not wish to say 0K, for obvious reason), but as calculations show would not make much difference whether one assumes 100 or 1000K as a starting point.
Thanks.
Sorry, my sloppy typing into Excel
T=(0.1*10^8/5.6)^0.25 = 36.5
and not
T= (0.1*10^8/5.6)^0.26 = 42.2
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Leif Svalgaard (06:00:48)
“I think you have gone off-topic at length with personal attacks instead of answering my simple question as to where there tha challenge lies. My question still stands.”
Leif, I have not launched any personal attacks, but I have responded to a few.
People can agree to disagree respectfully. I professionally moderated online forums for years. I would have shut down the counter-policy conduct as soon as it started (and it’s not like I would have had a choice about it).
We’re all volunteers in this forum, so we have no authority to demand answers. I suggested that we leave the matter for another day when it might be on-topic in another thread.
I thanked you more than once for the answers you provided regarding solar science. I now thank you again for them: Thank You.
– – –
gary gulrud (06:50:08)
“I think the moderators here at WUWT are doing very well”
I agree, especially considering that they are volunteers (something I learned during this thread).
– – –
anna v (22:23:07)
“In my view, Paul wants to say that searching for a correlation in the time spectra of geomagnetic activity and temperature is not a simple thing as there are more variables than obvious entering which might mask correlations. […] We work with the data we are given.”
I will offer a few notes, in part to dispel innuendos [from others] suggesting that I might have some mysterious &/or thieving political motives:
–
In following these discussions I am concerned that some participants:
1) do not differentiate between correlation, phase concordance, & coupling.
2) have never carefully studied the variability of parameter estimates with variation of measurement (&/or summary) scale in the context of spatiotemporal heterogeneity.
3) do not instinctively consider (or acknowledge) the possibility of nonlinear relations.
4) fail to acknowledge (or fail to realize) that if someone says there is a relationship, it does not mean they are suggesting causation.
5) fail to acknowledge that there can be relationships in the absence of known mechanisms.
6) do not distinguish randomness from chaos.
7) do not instinctively consider lurking, conditioning, & contrast variables.
8) have possibly never been trained in the practice of data analysis, even if they may have been trained extensively in experimental design and formal hypothesis testing.
9) fail to emphasize the limitations of untenable assumptions.
10) prematurely draw conclusions (i.e. before looking under every stone).
11) fail to accurately qualify statistical interpretations and related statements.
Something which I find of particular concern is the seeming fixation on “global average annual temperature”. It should be instinctive that important signals are masked in global averages and that diurnal temperature range is a better variable for investigating some of the topics that seem to fascinate many readers. (And note: We have data.)
Considering the partial deterioration of the public’s trust in science due to the climate controversy, there will be ongoing scrutiny of science.
We all have different background & experience – and this is an interdisciplinary discussion. I acknowledge the value of access to comments from people with different experience.
–
I will end with a reminder of what caused me to start engaging in discussions like this one:
I saw projections showing that daily minimum temperatures are going to overtake daily maximum temperatures. These projections were made by an organization that calls itself an “Institute for Climate Studies”. This organization is funded by a government that has implemented a substantial carbon tax. (Note: I have verified that many other jurisdictions employ the same methodology.)
If modeled future nighttime temperatures are allowed to regularly exceed daytime temperatures, what effect does this have on forecasted mean temperatures if mean temperature is defined as the average of max & min?
The need for transparency & audit is clear, particularly given the backlash.
Paul Vaughan (14:47:31) :
Leif, I have not launched any personal attacks
You most certainly have, like insinuating that my polite requests for clarifications were ‘insults’ and ‘badgerings’.
People can agree to disagree respectfully
The problem is that you will not even tell me what you disagree with. That is most disrespectful, IMHO.
But I realize that it may be completely hopeless to get a reasonable answer out of you, so shall stop trying for now. (Sigh).
Leif Svalgaard (15:14:44)
“[…] That is most disrespectful, IMHO.”
No disrespect is intended.
I have tremendous respect for you.
You are a highly esteemed member of [more than] this community.
Leif Svalgaard (15:14:44)
“You most certainly have”
I object to this statement (and for clarity: I do not wish to debate this).
My thanks for your answers to questions about solar science are sincere.
Leif Svalgaard (15:14:44)
“The problem is that you will not even tell me what you disagree with.”
I object to this statement (and for clarity: I do not wish to debate this).
–
Leif: “[…] so shall stop trying for now.”
To be explicit: Please do not resume trying.
–
Your answers to questions about solar science are valued.
Leif Svalgaard (15:14:44) :
“People can agree to disagree respectfully”
The problem is that you will not even tell me what you disagree with. That is most disrespectful, IMHO.
Even as you claim no disrespect was intended, I consider it very disrespectful for you to state that you challenge a statement of mine, but will not tell me what the challenge is. You will rather spend a inordinately large bandwidth complaining about me badgering you and saying that since this is all volunteer work one cannot demand to know. Where I come from it is a right to be confronted with the particulars of a challenge. Trampling that right [as you do] is most disturbing and unsatisfactory. Now, I realize that you have raised 11 points or complaints about ‘some’ participants. Would you tell me which of those apply to me in your opinion, so I can seek help or try to amend my ways?
Paul Vaughan (16:22:52) :
“The problem is that you will not even tell me what you disagree with.”
I object to this statement (and for clarity: I do not wish to debate this).
And in the end that is actually fine with me [in spite of my badgering]. It simply tells me not to take seriously any challenges issued by you [which I was doing, as is my wont], and to disregard any and all such.
Leif Svalgaard (16:27:02)
“Where I come from […]”
Leif Svalgaard (16:55:42)
“It simply tells me not to take seriously […]”
Perhaps we have different cultural roots. That does not change my respect for your knowledge about solar science, nor will it ever cause me to dismiss all of your future claims in advance.
Paul Vaughan (20:42:08) :
That does not change my respect for your knowledge about solar science,
Perhaps forgetting that my initial training was atmospheric physics.
nor will it ever cause me to dismiss all of your future claims in advance.
And why would someone ever even think of doing so? We are indeed from different cultures.
Thanks for the explanation Leif. I was handwriting the equations to follow the logic. I still need to comprehend more but your equation seems to describe the major effect that drives temp as a function of solar radiance. I’ll probably think about it some more this weekend since I don’t probably understand as much as I’d like to right now. Intuitively, I think that there should be other factors that need to be included (like if albedo changes or water vapor can modify dT) but I haven’t come up with anything definitive yet (and may not). It may simply be an elegant equation that works throughout the universe for spherical bodies.
The letter to the editor in S&T was favorable. It was a response to an article written on Sun and Global Warming. You were acknowledged as a person who predicted a slow beginning to a slow beginning to cycle 24 and it being a weak cycle (“the weakest in a century”) as documented in S&T July 2007, page 29.
alphajuno (21:51:12) :
I’ll probably think about it some more this weekend since I don’t probably understand as much as I’d like to right now.
If you have any specific questions or need some further explanation, just shoot me a question. I’ll be monitoring this thread for such. The equation is not original with me, but is the ‘usual’ equation being taught [and actually works even for non-spherical bodies]. The only assumption in all of this is that the body is in radiative equilibrium, i.e. it radiates away what comes in [in the long run].
Leif Svalgaard
I am trying to understand a bit more about solar flares – I have read some basic stuff by googling but have not found a good trend analysis.
Are data tracked and kept – I think I read somewhere that solar flares peak slightly later in the solar cycle then sunspots? If so where can I find it?
Are they used as a predictor of cycle length?
I understand that solar flare activity is difficult to predict – who are the leading people on this and do you know any good source material that can help me in my quest to learn more?
Grateful as ever. Thanks.
PaulHClark (09:07:32) :
Are data tracked and kept – I think I read somewhere that solar flares peak slightly later in the solar cycle then sunspots? If so where can I find it?
http://www.ngdc.noaa.gov/stp/stp.html
is a good source.
Are they used as a predictor of cycle length?
No, and the cycle length is a rather meaningless number, anyway. The actual activity levels are much better.
I understand that solar flare activity is difficult to predict – who are the leading people on this and do you know any good source material that can help me in my quest to learn more?
Flare research has taken a backseat to CME research lately, but lots of people are still doing this. Spiro Antiochos is one of my favorites [and a good friend]. google him.
PaulHClark (09:07:32) :
I am trying to understand a bit more about solar flares
There is good stuff here too:
http://sprg.ssl.berkeley.edu/~tohban/wiki/index.php/RHESSI_Science_Nuggets
Error in the record:
At (16:27:02) Leif Svalgaard quotes Leif Svalgaard (15:14:44) as saying:
“People can agree to disagree respectfully”
–
Correction:
Paul Vaughan (14:47:31)
“People can agree to disagree respectfully.”
–
I would add:
They can also choose to do so efficiently.
(Freedom is practical.)
– – –
Leif Svalgaard (21:30:31)
“[…] my initial training was atmospheric physics.”
I respect this – thank you for pointing it out.