For the first time – a mysterious notch filter found in the climate. The EEs among us will recognize this kind of plot.
In EE work it is called a Bode Plot.
Super Nova Of A Climate Paper
In EE work it is called a Bode Plot.
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In EE work it is called a Bode Plot.
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22 responses to “Super Nova Of A Climate Paper”
All that says is that the global mean temperature is relatively insensitive to short-term variations in solar irradiance.
Not to mention they’re doing fourier transforms out to a 2500-year period with only 400 years of data. Theoretically possible, but the uncertainty swamps the signal.
Neil,
Quite right about the short term.
The mechanism will be explained in future posts.
I’m trying to understand the physical meaning of the y scale. degrees c/Wm^2
So, Wm^2 is insolation intensity. But it’s not a plot of time vs input power, (which I’d expect) it’s sensitivity of the temperature to variations of input power. What does that mean? And why would that have a time dependance with a notch at 11 years? Sunspot activity affects atmospheric heat retention??? Sunspots do what? I’m guessing either the atmosphere expands which affects heat retention, or they affect cloud formation with the same result (or both) or???
Fun fact: Electronic music pioneer Harald Bode who worked with Bob Moog and Hendrik Bode (plotfather) are different people. I didn’t know that until recently.
Simon,
I’ve re-read that article and a lot of the comments. The problem I have with the idea of a “11-year notch filter” is that the transfer function is pretty much just the inverse of the input signal. Normally when I see something like that, I would say that the system is simply non-responsive to the input. I would not say that there is coincidentally a notch filter or a bandpass at every single relevant frequency!
Neil,
Yes. For a physical system as described that is true. It is “equivalent” to a notch filter at that frequency.
Naturally, this will be widely reported.
Eric,
Actually no. One of the biggest sceptics around – Willis E. – doesn’t get it. His opinion is that you can’t actually describe what the transfer function of the climate system is.
And yet to the EE types commenting on the work it seems perfectly reasonable.
OTOH Monckton of Brenchly thinks quite highly of the work. But the exposition is not quite done so maybe the sceptics will come around.
The proof will be in the pudding. They intend to make predictions. If they come to pass the model will shown to have some skill. If not – interesting failure.
Neil,
I have rethought. The transfer function is not the inverse of the input signal (TSI). It is the result of what the climate system does to the input signal.
This:
http://motls.blogspot.com/2014/06/david-evans-notch-filter-theory-of.html
Makes a good case that it’s all an artifact of the analysis method.
MMM,
If the Climate is totally insensitive to TSI then the response line should be flat. No notch. The claim is that the notch shows up in Fourier Transform as well as the OFT.
Dave/Jo claim to have found a mechanism to explain the notch. We shall see.
Motl says, “But it must be either something else than the TSI, or the effect must be such that all the wiggles shorter than 20 years or so must be universally suppressed.”
And then goes on to discount “something else than the TSI” while also discounting the response at 3 years.
I’m seeing this a LOT among the sceptics of the theory.
There is a hole in their thinking because they are wedded to “TSI does not influence temps”. Amusing.
In any case it is amusing to see the “no response to small changes” orthodoxy. Compare with Dalton, Maunder, Oort, and other minimums.
Motl is in effect saying “low pass filter cut off at 20 years”. What explains the significant 3 year response then?
Willis is a sceptic:
http://wattsupwiththat.com/2014/06/06/sunspots-and-sea-surface-temperature/#comment-1664591
Simon,
That’s precisely my contention–the response is nearly flat.
Perhaps it rolls off by approximately 1/3 over the frequency range, but it’s pretty flat. Much flatter than the stimulus. What’s more, we can observe that it’s pretty flat–average temperature doesn’t really change much over 10 or 20 years. Certainly nothing like our one-year cycle of spring, summer, fall, winter.
The stimulus, on the other hand has big, obvious, and well-documented peaks and valleys, and TSI changes quite dramatically and cyclically.
So if you divide the response by the stimulus, you get a transfer function that is essentially the inverse of the stimulus, with troughs where the stimulus has peaks and peaks where the stimulus has troughs.
That looks to me as though the climate is simply insensitive to TSI on shorter time scales. Not that there is a “filter” at any particular frequency.
Neil,
So what is the mechanism for “troughs where the stimulus has peaks and peaks where the stimulus has troughs.”
Which says out of phase signal derived from the the input. How do you get that? Except the phase is more exactly out of phase at 11 years.
Where is your inverter? And why is the “tuning” of the inverter most exact at 11 years?
I’m betting on Monckton who has seen the whole paper. He thinks Dave/Jo are on to something.
Simon June 17th, 2014 (#):
Hogwash. I’ve never said anything of the sort. Please have the common decency to quote what I actually said. I can defend my own words. I cannot defend your fantasy about what I said.
Sorry to be so harsh, but I’m very tired of being accused of saying things I’ve never said.
w.
Neil June 17th, 2014 (#):
Thank you very much, Neil! I’ve been trying to get people to understand that, with little success.
w.
Simon June 17th, 2014 (#):
No, it’s not “equivalent” to a notch filter just because both would create a notch. That’s like saying that a bullet hole is “equivalent” to a hole in the ground because they are both holes.
The usual interpretation of the situation, as Neil said, is that:
And that is a very different thing, which would have a different underlying mechanism than a “notch filter”.
Note that this Dave Evans (the “notch filter” theory man) and I don’t disagree about the notch.
We just disagree about what is the mechanism behind it.
I say that the system is non-responsive to the input because of the emergent phenomena which thermally regulate the temperature and restrict it to very narrow bounds (e. g., a mere ± 0.03°C variation in global temperature over the 20th century). Can you say “non-responsive to changes in forcing”? Because the climate is clearly that.
Dave Evans and Jo Nova, on the other hand, say that the mechanism is something I’ve never even heard of—a thermal notch filter.
Can anyone reading this thread give me a single example of such a chimera?
w.
PS—References on request for my hypothesis about how the climate actually works. You might start with my post entitled Emergent Climate Phenomena
Here is something I left at WUWT. It is in moderation:
You just made that up out of the whole cloth.
Well no. You haven’t read the paper.
So lets see. There is a magnetic cycle that is anti-phase to the sun-spot cycle.
And then there was the hint about albedo. Maybe the magnetic field affects the albedo. Maybe through cosmic rays. That would provide signal cancellation (the notch). That would be why it takes two cycles for the signal to show up. And imperfect cancellation might very well explain the hump at three years.
As to being crazy – well as an engineer it has helped me solve problems a LOT faster than other engineers. After all I moved up from bench technician to aerospace engineer sans degree of any kind. Not too shabby. My method is to see a pattern and see if I can find the causes. In other words I get a clue and look for causes. In this case I’ll just have to wait.
So far the people who get it are EEs. The rest of you are more or less in the dark. I find that highly amusing. But I get Dave’s methods. Standard DSP/electronics stuff. And the notch gave him a clue. But his wife (Jo) solved the problem. I’m sure the uproar has made them closer.
BTW did you see this?
http://www.nbcnews.com/science/science-news/low-cost-fusion-project-steps-out-shadows-looks-money-n130661
I got a mention. So I’m not just an EE either. And let me just say that money is not a problem. They are looking so the article is not telling a lie. Maybe I can tell you the whole story some time down the road. The whole AGW scam will be coming apart on many fronts. The Jo/Dave thing is just one of them.
And one other thing. I’m an old usenet hand. Hard arguments and insults don’t move me. So fire away. Hunter S. Thompson once told me on usenet that he liked my writing. It is a fun life. I’m enjoying the hell out of it.
Maybe later when this all calms down we can collaborate on some interesting stuff. I have some ideas.
I look forward to pulling the rug out from under those communists we used to know.
I don’t think in the main what is going on is an Emergent Phenomenon. The emergent stuff is at the margins.
Simon,
So what is the mechanism for “troughs where the stimulus has peaks and peaks where the stimulus has troughs.”
I don’t know, but I sure as heck wouldn’t be looking for it just at the 11-year period. I’d be looking at everything under 100 years at least. It’s a broadband response.
That “notch filter” is a red herring.
Neil,
If you are following along at JoNova’s it is not.
http://jonova.s3.amazonaws.com/cfa/solar-radiation-peaks-magnetic-field-b.gif
Other than the notch-
Something I’d expect out of a (at least partly) chaotic system like climate is 1/f noise. That would look like a 3dB/octave roll off. Kinda sorta looks like that, doesn’t it.
Thing Motl did seem to have trouble understanding is that one of the claims is that the climate is an infinite impulse response filter. He only seem,s to be familiar with non-recursive digital filters. Any exponentially decaying filter is IIR,(think RC low pass, the voltage on the capacitor is always a function of where it’s been for all previous time) so I don’t see any reason the climate wouldn’t be one, at least to first approximation.
One might expect a correlation between sunspot activity and global temp to show up directly in the temperature data, no extensive data massaging needed, no DFTs, FFTs or BLTs etc.