Comments on: A New Spaghetti Graph http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/ by Steve McIntyre Thu, 20 Jun 2013 02:13:38 +0000 hourly 1 http://wordpress.com/ By: Steve McIntyre http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47673 Fri, 23 Nov 2007 21:00:24 +0000 http://www.climateaudit.org/?p=615#comment-47673 Bump. Here’s the sort of analysis that I’d like to do if we can get regression coefficients from RegEM TTLS. We can then group the proxies by continent and class and calculate the contribution of each group and compare that to the contribution of Graybill bristlecone chronologies. As you seen in the graphics of this post, everything other than GRaybill chronologies is pretty much noise in the MBH98 network.

If RegEM TTLS is yielding results “remarkably similar” to MBH98, my guess is that the graph allocating contributions will be “remarkably similar” to what I’ve shown here.

]]> By: jae http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47672 Tue, 04 Apr 2006 19:19:55 +0000 http://www.climateaudit.org/?p=615#comment-47672 I suppose someone has already mentioned this, but just in case: Even if you allow the BPs, foxtails and other questionable series to be included in the reconstructions, the fact that they ALONE impart a hockey stick curve to otherwise relatively trendless data PROVES that the reconstructions do not represent the NH, let alone the global trend. They reflect a “localized phenomonen.” Hmmm, it seems that I have seen that argument used before by certain scientists concerning the existence of the MWP… So, it doesn’t really matter a bit what caused the striking growth patterns of these localized groups of trees, relative to the notion of NH or global warming.

]]> By: TCO http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47671 Mon, 03 Apr 2006 02:28:42 +0000 http://www.climateaudit.org/?p=615#comment-47671 1. When you say that you’ve “gotten the MBH reconstruction with the 15th century proxies”, to what extent did you follow the procedure in the overall MBH HS?
2. How much work involved in doing the same experiment with all the proxies? And how relevant would it be?
3. Why did you pick the 15th century? Does it help your story over other time frames?
4. From the chart it looks like the bristlecones are giving a lot of weighting. About (negative) 25% over much of the time period. Would it be possible to say how much of the HS index comes from each group? I think this is a different issue than just total weighting, but not sure. How about just averaging over time and saying how much each group and in particular the bcps weight the reconstruction? Would actually be interesting to see a table of this proxy by proxy.
5. The negative weighting of so many series is fascinating. It sure points out how much some of these are just chaff.
6. Is it possible to show the same thing for the overall experiment (the way MBH was run…not just the 15th century stuff). So we can tell what is affecting things within the HS itself?
7. Fascinating that you stick up for the concept that proxies are just peices of the puzzle and that the HS is a linear combination, but that some of the howler monkeys (maybe even Ross) want to say that it is impossible to isolate flaw extents, or to savage me for being interested in it, or to “inform me what I didn’t know (haha)” that some flaws that are small in extent are still interesting for embarressment/caution reasons.
8. What the hell are SH proxies doing in a NH reconstruction?
9. What’s going on in your “standard way of showing” bottom graph? What’s the axis? Did you normalize each series by its own variance?

]]> By: Steve McIntyre http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47670 Sun, 02 Apr 2006 23:38:20 +0000 http://www.climateaudit.org/?p=615#comment-47670 Luboà…⟬ I did a post on the Tang et al article last summer here http://www.climateaudit.org/?p=329 . I thought that it was a pretty interesting article.

]]> By: Paul Linsay http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47669 Sun, 02 Apr 2006 19:56:26 +0000 http://www.climateaudit.org/?p=615#comment-47669 #19: But notice the earlier statement “Because of bristlecone pine’s intolerance to shading…” indicating that it is sensitive to sunlight or equivalently cloud cover. They don’t seem to take that into account in their mean annual growth rates.

]]> By: Luboš Motl http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47668 Sun, 02 Apr 2006 17:48:03 +0000 http://www.climateaudit.org/?p=615#comment-47668 http://www.ingentaconnect.com/content/bsc/gcb/1999/00000005/00000001/art00204

The paper above argues in favor of CO2 fertilization of bristlecones. It compares two “races” of the tree and shows that they both increased the water-use efficiency W, but they distributed the extra carbon differently among different parts of the trees.

http://links.jstor.org/sici?sici=0003-0031(198010)104%3A2%3C242%3AEROBP%3E2.0.CO%3B2-%23

Organic carbon, clay, and mean air temperature accounted for 83% or 55% of the growth for two types of bristlecones in the article above.

]]> By: Luboš Motl http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47667 Sun, 02 Apr 2006 17:21:50 +0000 http://www.climateaudit.org/?p=615#comment-47667 Dear Steve,
thanks, we’re on the same page.

Another silly comment of mine: I feel that these whole sectors of science are done without the physics approach – especially without smart experiments designed to find something out.

Has someone picked 20 bristlecones, give some of them more CO2, some of them more heat, some of them more moisture, some of them more Carbon 14, and so on, and just experimentally measure how the different quantities influence their tree ring width and growth?

The people in these fields just wait for random decisions of Mother Nature, which are always rather fuzzy and ill-defined, and then try to extract the signals and invent random correlations. It’s like if physicists in the 1940s were waiting when enough Uranium gets together and an accidental explosion of the atomic bomb occurs.

Best wishes
Lubos

]]> By: Pat Frank http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47666 Sun, 02 Apr 2006 09:52:03 +0000 http://www.climateaudit.org/?p=615#comment-47666 “If I overlaid the final reconstruction on this graphic, it overlaps the bristlecone contribution almost exactly.”

When I looked at Figure 1, I was struck immediately, almost shocked, by how much the BCP series looked like the MBH98 reconstruction. I’d sure like to see them scaled to a common zero and total intensity, and plotted over one another; especially with a difference residuals plot.

If I understand your plots correctly, Steve, the top panel shows all the various series scaled to MBH98 normal. The BCP series, in addition, is just offset to the center line of MBH98 to show its extreme similarity to MBH98. The bottom panel includes all the series, including the BCP series, all at normalized intensities, with a common zero line. Is that about it?

What a graphic! Your point that all the rest of the proxies merely add noise (and hence a visual authenticity) is perfectly displayed.

Questions: Is scaling everything to a normal sd before averaging valid in proxy production, or do people weight each given regional series by the number of trees in that series before averaging? Also when averaging, say, an O-18 proxy with a tree ring proxy, are they weighted by their native sd’s? Silly questions, perhaps.

]]> By: Hans Erren http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47665 Sun, 02 Apr 2006 07:33:50 +0000 http://www.climateaudit.org/?p=615#comment-47665 re #14
I’ll second that request.

]]> By: Louis Hissink http://climateaudit.org/2006/03/31/a-new-spaghetti-graph/#comment-47664 Sun, 02 Apr 2006 04:20:22 +0000 http://www.climateaudit.org/?p=615#comment-47664 Re #4

Steve

No, it’s ok as it is – was curious about both having 0 but scaled differently.

Thanks for the clarification.

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